Microorganisms and methods for producing alkenes

ABSTRACT

The invention provides non-naturally occurring microbial organisms containing an alkene pathway having at least one exogenous nucleic acid encoding an alkene pathway enzyme expressed in a sufficient amount to convert an alcohol to an alkene. The invention additionally provides methods of using such microbial organisms to produce an alkene, by culturing a non-naturally occurring microbial organism containing an alkene pathway as described herein under conditions and for a sufficient period of time to produce an alkene.

This application claims the benefit of priority of U.S. Provisionalapplication Ser. No. 61/535,893, filed Sep. 16, 2011, the entirecontents of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to biosynthetic processes, andmore specifically to organisms having an alkene biosynthetic capability.

Alkenes are commonly produced by cracking the alkanes found in crudeoil. Cracking uses heat and a catalyst to decompose alkanes. Generally,alkenes are unsaturated hydrocarbons with one double bond (R—C═C—R).Because of to the inherent property of alkenes being more reactive thanalkanes due to the presence of a double bond, alkenes are frequentlyused in the manufacture of plastics. For example, alkenes are used inthe manufacture of polyethene, polyvinylchloride (PVC) and Teflon. Loweralkenes, which are obtained by the cracking of kerosene or petrol, arealso commonly used as fuel and illuminant. Some alkenes, such as1,3-butadiene, styrene and propylene, are particularly useful inmanufacturing.

Over 25 billion pounds of butadiene (1,3-butadiene, BD) are producedannually and is applied in the manufacture of polymers such as syntheticrubbers and ABS resins, and chemicals such as hexamethylenediamine and1,4-butanediol. Butadiene is typically produced as a by-product of thesteam cracking process for conversion of petroleum feedstocks such asnaphtha, liquefied petroleum gas, ethane or natural gas to ethylene andother olefins. The ability to manufacture butadiene from alternativeand/or renewable feedstocks would represent a major advance in the questfor more sustainable chemical production processes

One possible way to produce butadiene renewably involves fermentation ofsugars or other feedstocks to produce diols, such as 1,4-butanediol or1,3-butanediol, which are separated, purified, and then dehydrated tobutadiene in a second step involving metal-based catalysis. Directfermentative production of butadiene from renewable feedstocks wouldobviate the need for dehydration steps and butadiene gas (bp −4.4° C.)would be continuously emitted from the fermenter and readily condensedand collected. Developing a fermentative production process wouldeliminate the need for fossil-based butadiene and would allowsubstantial savings in cost, energy, and harmful waste and emissionsrelative to petrochemically-derived butadiene.

Styrene is the precursor to polystyrene and numerous copolymers. Styrenebased products include, acrylonitrile 1,3-butadiene styrene (ABS),styrene-1,3-butadiene (SBR) rubber, styrene-1,3-butadiene latex, SIS(styrene-isoprene-styrene), S-EB-S (styrene-ethylene/butylene-styrene),styrene-divinylbenzene (S-DVB), and unsaturated polyesters. Thesematerials are used in rubber, plastic, insulation, fiberglass, pipes,automobile and boat parts, food containers, and carpet backing.

Styrene is most commonly produced by the catalytic dehydrogenation ofethylbenzene. Ethylbenzene is mixed in the gas phase with 10-15 timesits volume in high-temperature steam, and passed over a solid catalystbed. Most ethylbenzene dehydrogenation catalysts are based on iron(III)oxide, promoted by several percent potassium oxide or potassiumcarbonate. Steam serves several roles in this reaction. It is the sourceof heat for powering the endothermic reaction, and it removes coke thattends to form on the iron oxide catalyst through the water gas shiftreaction. The potassium promoter enhances this decoking reaction. Thesteam also dilutes the reactant and products, shifting the position ofchemical equilibrium towards products. A typical styrene plant consistsof two or three reactors in series, which operate under vacuum toenhance the conversion and selectivity. Typical per-pass conversions areca. 65% for two reactors and 70-75% for three reactors.

Propylene is produced primarily as a by-product of petroleum refiningand of ethylene production by steam cracking of hydrocarbon feedstocks.Propene is separated by fractional distillation from hydrocarbonmixtures obtained from cracking and other refining processes. Typicalhydrocarbon feedstocks are from non-renewable fossil fuels, such aspetroleum, natural gas and to a much lesser extent coal. Over 75 billionpounds of propylene are manufactured annually, making it the secondlargest fossil-based chemical produced behind ethylene. Propylene is abase chemical that is converted into a wide range of polymers, polymerintermediates and chemicals. Some of the most common derivatives ofchemical and polymer grade propylene are polypropylene, acrylic acid,butanol, butanediol, acrylonitrile, propylene oxide, isopropanol andcumene. The use of the propylene derivative, polypropylene, in theproduction of plastics, such as injection moulding, and fibers, such ascarpets, accounts for over one-third of U.S. consumption for thisderivative. Propylene is also used in the production of synthetic rubberand as a propellant or component in aerosols.

The ability to manufacture propylene from alternative and/or renewablefeedstocks would represent a major advance in the quest for moresustainable chemical production processes. One possible way to producepropylene renewably involves fermentation of sugars or other feedstocksto produce the alcohols 2-propanol (isopropanol) or 1-propanol, which isseparated, purified, and then dehydrated to propylene in a second stepinvolving metal-based catalysis. Direct fermentative production ofpropylene from renewable feedstocks would obviate the need fordehydration. During fermentative production, propylene gas would becontinuously emitted from the fermenter, which could be readilycollected and condensed. Developing a fermentative production processwould also eliminate the need for fossil-based propylene and would allowsubstantial savings in cost, energy, and harmful waste and emissionsrelative to petrochemically-derived propylene.

Thus, there exists a need for alternative methods for effectivelyproducing commercial quantities of alkenes. The present inventionsatisfies this need and provides related advantages as well.

SUMMARY OF INVENTION

The invention provides non-naturally occurring microbial organismscontaining an alkene pathway having at least one exogenous nucleic acidencoding an alkene pathway enzyme expressed in a sufficient amount toconvert an alcohol to an alkene. In some aspects of the invention, themicrobial organism comprises an alkene pathway selected from: (1) analcohol kinase and a phosphate lyase; (2) a diphosphokinase and adiphosphate lyase; and (3) an alcohol kinase, an alkyl phosphate kinaseand a diphosphate lyase. The invention additionally provides methods ofusing such microbial organisms to produce an alkene, by culturing anon-naturally occurring microbial organism containing an alkene pathwayas described herein under conditions and for a sufficient period of timeto produce an alkene.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the conversion of an alcohol substrate to an alkene viaalkyl phosphate or alkyl diphosphate intermediates. Enzymes are A.alcohol kinase, B. phosphate lyase, C. diphosphokinase, D. alkylphosphate kinase and E. diphosphate lyase. R¹, R², R³, and R⁴ are eachindependently (a) hydrogen, cyano, halo, or nitro; (b) C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl,heteroaryl, or heterocyclyl, each optionally substituted with one ormore substituents Q; or (c) —C(O)R^(1a), —C(O)OR^(1a),—C(O)NR^(1b)R^(1c), —C(NR^(1a))NR^(1b)R^(1c), —OR^(1a), —OC(O)R^(1a),—OC(O)OR^(1a), —OC(O)NR^(1b)R^(1c), —OC(═NR^(1a))NR^(1b)R^(1c),—OS(O)R^(1a), —OS(O)₂R^(1a), —OS(O)NR^(1b)R^(1c), —OS(O)₂NR^(1b)R^(1c),NR^(1b)NR^(1c), —NR^(1a)C(O)R^(1d), —NR^(1a)C(O)OR^(1d),—NR^(1a)C(O)NR^(1b)R^(1c), —NR^(1a)C(═NR^(1d))NR^(1b)R^(1c),—NR^(1a)S(O)R^(1d), —NR^(1a)S(O)₂R^(1d), —NR^(1a)S(O)NR^(1b)R^(1c),—NR^(1a)S(O)₂NR^(1b)R^(1c), —SR^(1a), —S(O)R^(1a), —S(O)₂R^(1a),—S(O)NR^(1b)R^(1c), or —S(O)₂NR^(1b)R^(1c); wherein each R^(1a), R^(1b),R^(1c), and R^(1d) is independently hydrogen, C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, orheterocyclyl; or R^(1a) and R^(1c) together with the C and N atoms towhich they are attached form heterocyclyl; or R^(1b) and R^(1c) togetherwith the N atom to which they are attached form heterocyclyl; whereineach Q is independently selected from (a) oxo, cyano, halo, and nitro;(b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl,C₇₋₁₅ aralkyl, heteroaryl, and heterocyclyl, each of which is furtheroptionally substituted with one or more, in one embodiment, one, two,three, or four, substituents Q^(a); and (c) —C(O)R^(a), —C(O)OR^(a),—C(O)NR^(b)R^(c), —C(NR^(a))NR^(b)R^(c), —OR^(a), —OC(O)R^(a),—OC(O)OR^(a), —OC(O)NR^(b)R^(c), —OC(═NR^(a))NR^(b)R^(c), —OS(O)R^(a),—OS(O)₂R^(a), —OS(O)NR^(b)R^(c), —OS(O)₂NR^(b)R^(c), —NR^(b)R^(c),—NR^(a)C(O)R^(d), —NR^(a)C(O)OR^(d), —NR^(a)C(O)NR^(b)R^(c),—NR^(a)C(═NR^(d))NR^(b)R^(c), —NR^(a)S(O)R^(d), —NR^(a)S(O)₂R^(d),—NR^(a)S(O)NR^(b)R^(c), —NR^(a)S(O)₂NR^(b)R^(c), —SR^(a), —S(O)R^(a),—S(O)₂R^(a), —S(O)NR^(b)R^(c), and —S(O)₂NR^(b)R^(c), wherein eachR^(a), R^(b), R^(c), and R^(d) is independently (i) hydrogen; (ii) C₁₋₆alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅aralkyl, heteroaryl, or heterocyclyl, each optionally substituted withone or more, in one embodiment, one, two, three, or four, substituentsQ^(a); or (iii) R^(b) and R^(c) together with the N atom to which theyare attached form heterocyclyl, optionally substituted with one or more,in one embodiment, one, two, three, or four, substituents Q^(a); whereineach Q^(a) is independently selected from the group consisting of (a)oxo, cyano, halo, and nitro; (b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, andheterocyclyl; and (c) —C(O)R^(e), —C(O)OR^(e), —C(O)NR^(f)R^(g),—C(NR^(e))NR^(f)R^(g), —OR^(e), —OC(O)R^(e), —OC(O)OR^(e),—OC(O)NR^(f)R^(g), —OC(═NR^(e))NR^(f)R^(g), —OS(O)R^(e), —OS(O)₂R^(e),—OS(O)NR^(f)R^(g), —OS(O)₂NR^(f)R^(g), —NR^(f)R^(g), —NR^(e)C(O)R^(h),—NR^(e)C(O)OR^(f), —NR^(e)C(O)NR^(f)R^(g), —NR^(e)C(═NR^(h))NR^(f)R^(g),—NR^(e)S(O)R^(h), —NR^(e)S(O)₂R^(h), —NR^(e)S(O)NR^(f)R^(g),—NR^(e)S(O)₂NR^(f)R^(g), —SR^(e), —S(O)R^(e), —S(O)₂R^(e),—S(O)NR^(f)R^(g), and —S(O)₂NR^(f)R^(g); wherein each R^(e), R^(f),R^(g), and R^(h) is independently (i) hydrogen; (ii) C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl,heteroaryl, or heterocyclyl; or (iii) R^(f) and R^(g) together with theN atom to which they are attached form heterocyclyl.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to the design and production of cellsand organisms having biosynthetic production capabilities for alkenes.The invention, in particular, relates to the design of microbialorganism capable of producing alkene by introducing one or more nucleicacids encoding an alkene pathway enzyme.

In one embodiment, the invention utilizes in silico stoichiometricmodels of Escherichia coli metabolism that identify metabolic designsfor biosynthetic production of alkenes. The results described hereinindicate that metabolic pathways can be designed and recombinantlyengineered to achieve the biosynthesis of alkenes in Escherichia coliand other cells or organisms. Biosynthetic production of alkenes, forexample, by the in silico designs can be confirmed by construction ofstrains having the designed metabolic genotype. These metabolicallyengineered cells or organisms also can be subjected to adaptiveevolution to further augment alkene biosynthesis, including underconditions approaching theoretical maximum growth.

In certain embodiments, the alkene biosynthesis characteristics of thedesigned strains make them genetically stable and particularly useful incontinuous bioprocesses. Separate strain design strategies wereidentified with incorporation of different non-native or heterologousreaction capabilities into E. coli or other host organisms leading toalkene producing metabolic pathways from alcohols that are producednaturally or that are produced through genetic engineering. In silicometabolic designs were identified that resulted in the biosynthesis ofalkenes in microorganisms from this substrate or metabolicintermediates.

Strains identified via the computational component of the platform canbe put into actual production by genetically engineering any of thepredicted metabolic alterations, which lead to the biosyntheticproduction of alkenes or other intermediate and/or downstream products.In yet a further embodiment, strains exhibiting biosynthetic productionof these compounds can be further subjected to adaptive evolution tofurther augment product biosynthesis. The levels of product biosynthesisyield following adaptive evolution also can be predicted by thecomputational component of the system.

As used herein, the term “non-naturally occurring” when used inreference to a microbial organism or microorganism of the invention isintended to mean that the microbial organism has at least one geneticalteration not normally found in a naturally occurring strain of thereferenced species, including wild-type strains of the referencedspecies. Genetic alterations include, for example, modificationsintroducing expressible nucleic acids encoding metabolic polypeptides,other nucleic acid additions, nucleic acid deletions and/or otherfunctional disruption of the microbial organism's genetic material. Suchmodifications include, for example, coding regions and functionalfragments thereof, for heterologous, homologous or both heterologous andhomologous polypeptides for the referenced species. Additionalmodifications include, for example, non-coding regulatory regions inwhich the modifications alter expression of a gene or operon. Exemplarymetabolic polypeptides include enzymes or proteins within an alkenebiosynthetic pathway.

A metabolic modification refers to a biochemical reaction that isaltered from its naturally occurring state. Therefore, non-naturallyoccurring microorganisms can have genetic modifications to nucleic acidsencoding metabolic polypeptides, or functional fragments thereof.Exemplary metabolic modifications are disclosed herein.

As used herein, the term “isolated” when used in reference to amicrobial organism is intended to mean an organism that is substantiallyfree of at least one component as the referenced microbial organism isfound in nature. The term includes a microbial organism that is removedfrom some or all components as it is found in its natural environment.The term also includes a microbial organism that is removed from some orall components as the microbial organism is found in non-naturallyoccurring environments. Therefore, an isolated microbial organism ispartly or completely separated from other substances as it is found innature or as it is grown, stored or subsisted in non-naturally occurringenvironments. Specific examples of isolated microbial organisms includepartially pure microbes, substantially pure microbes and microbescultured in a medium that is non-naturally occurring.

As used herein, the terms “microbial,” “microbial organism” or“microorganism” are intended to mean any organism that exists as amicroscopic cell that is included within the domains of archaea,bacteria or eukarya. Therefore, the term is intended to encompassprokaryotic or eukaryotic cells or organisms having a microscopic sizeand includes bacteria, archaea and eubacteria of all species as well aseukaryotic microorganisms such as yeast and fungi. The term alsoincludes cell cultures of any species that can be cultured for theproduction of a biochemical.

As used herein, the term “substantially anaerobic” when used inreference to a culture or growth condition is intended to mean that theamount of oxygen is less than about 10% of saturation for dissolvedoxygen in liquid media. The term also is intended to include sealedchambers of liquid or solid medium maintained with an atmosphere of lessthan about 1% oxygen.

“Exogenous” as it is used herein is intended to mean that the referencedmolecule or the referenced activity is introduced into the hostmicrobial organism. The molecule can be introduced, for example, byintroduction of an encoding nucleic acid into the host genetic materialsuch as by integration into a host chromosome or as non-chromosomalgenetic material such as a plasmid. Therefore, the term as it is used inreference to expression of an encoding nucleic acid refers tointroduction of the encoding nucleic acid in an expressible form intothe microbial organism. When used in reference to a biosyntheticactivity, the term refers to an activity that is introduced into thehost reference organism. The source can be, for example, a homologous orheterologous encoding nucleic acid that expresses the referencedactivity following introduction into the host microbial organism.Therefore, the term “endogenous” refers to a referenced molecule oractivity that is present in the host. Similarly, the term when used inreference to expression of an encoding nucleic acid refers to expressionof an encoding nucleic acid contained within the microbial organism. Theterm “heterologous” refers to a molecule or activity derived from asource other than the referenced species whereas “homologous” refers toa molecule or activity derived from the host microbial organism.Accordingly, exogenous expression of an encoding nucleic acid of theinvention can utilize either or both a heterologous or homologousencoding nucleic acid.

It is understood that when more than one exogenous nucleic acid isincluded in a microbial organism that the more than one exogenousnucleic acids refers to the referenced encoding nucleic acid orbiosynthetic activity, as discussed above. It is further understood, asdisclosed herein, that such more than one exogenous nucleic acids can beintroduced into the host microbial organism on separate nucleic acidmolecules, on polycistronic nucleic acid molecules, or a combinationthereof, and still be considered as more than one exogenous nucleicacid. For example, as disclosed herein a microbial organism can beengineered to express two or more exogenous nucleic acids encoding adesired pathway enzyme or protein. In the case where two exogenousnucleic acids encoding a desired activity are introduced into a hostmicrobial organism, it is understood that the two exogenous nucleicacids can be introduced as a single nucleic acid, for example, on asingle plasmid, on separate plasmids, can be integrated into the hostchromosome at a single site or multiple sites, and still be consideredas two exogenous nucleic acids. Similarly, it is understood that morethan two exogenous nucleic acids can be introduced into a host organismin any desired combination, for example, on a single plasmid, onseparate plasmids, can be integrated into the host chromosome at asingle site or multiple sites, and still be considered as two or moreexogenous nucleic acids, for example three exogenous nucleic acids.Thus, the number of referenced exogenous nucleic acids or biosyntheticactivities refers to the number of encoding nucleic acids or the numberof biosynthetic activities, not the number of separate nucleic acidsintroduced into the host organism.

The non-naturally occurring microbial organisms of the invention cancontain stable genetic alterations, which refers to microorganisms thatcan be cultured for greater than five generations without loss of thealteration. Generally, stable genetic alterations include modificationsthat persist greater than 10 generations, particularly stablemodifications will persist more than about 25 generations, and moreparticularly, stable genetic modifications will be greater than 50generations, including indefinitely.

Those skilled in the art will understand that the genetic alterations,including metabolic modifications exemplified herein, are described withreference to a suitable host organism such as E. coli and theircorresponding metabolic reactions or a suitable source organism fordesired genetic material such as genes for a desired metabolic pathway.However, given the complete genome sequencing of a wide variety oforganisms and the high level of skill in the area of genomics, thoseskilled in the art will readily be able to apply the teachings andguidance provided herein to essentially all other organisms. Forexample, the E. coli metabolic alterations exemplified herein canreadily be applied to other species by incorporating the same oranalogous encoding nucleic acid from species other than the referencedspecies. Such genetic alterations include, for example, geneticalterations of species homologs, in general, and in particular,orthologs, paralogs or nonorthologous gene displacements.

An ortholog is a gene or genes that are related by vertical descent andare responsible for substantially the same or identical functions indifferent organisms. For example, mouse epoxide hydrolase and humanepoxide hydrolase can be considered orthologs for the biologicalfunction of hydrolysis of epoxides. Genes are related by verticaldescent when, for example, they share sequence similarity of sufficientamount to indicate they are homologous, or related by evolution from acommon ancestor. Genes can also be considered orthologs if they sharethree-dimensional structure but not necessarily sequence similarity, ofa sufficient amount to indicate that they have evolved from a commonancestor to the extent that the primary sequence similarity is notidentifiable. Genes that are orthologous can encode proteins withsequence similarity of about 25% to 100% amino acid sequence identity.Genes encoding proteins sharing an amino acid similarity less that 25%can also be considered to have arisen by vertical descent if theirthree-dimensional structure also shows similarities. Members of theserine protease family of enzymes, including tissue plasminogenactivator and elastase, are considered to have arisen by verticaldescent from a common ancestor.

Orthologs include genes or their encoded gene products that through, forexample, evolution, have diverged in structure or overall activity. Forexample, where one species encodes a gene product exhibiting twofunctions and where such functions have been separated into distinctgenes in a second species, the three genes and their correspondingproducts are considered to be orthologs. For the production of abiochemical product, those skilled in the art will understand that theorthologous gene harboring the metabolic activity to be introduced ordisrupted is to be chosen for construction of the non-naturallyoccurring microorganism. An example of orthologs exhibiting separableactivities is where distinct activities have been separated intodistinct gene products between two or more species or within a singlespecies. A specific example is the separation of elastase proteolysisand plasminogen proteolysis, two types of serine protease activity, intodistinct molecules as plasminogen activator and elastase. A secondexample is the separation of mycoplasma 5′-3′ exonuclease and DrosophilaDNA polymerase III activity. The DNA polymerase from the first speciescan be considered an ortholog to either or both of the exonuclease orthe polymerase from the second species and vice versa.

In contrast, paralogs are homologs related by, for example, duplicationfollowed by evolutionary divergence and have similar or common, but notidentical functions. Paralogs can originate or derive from, for example,the same species or from a different species. For example, microsomalepoxide hydrolase (epoxide hydrolase I) and soluble epoxide hydrolase(epoxide hydrolase II) can be considered paralogs because they representtwo distinct enzymes, co-evolved from a common ancestor, that catalyzedistinct reactions and have distinct functions in the same species.Paralogs are proteins from the same species with significant sequencesimilarity to each other suggesting that they are homologous, or relatedthrough co-evolution from a common ancestor. Groups of paralogousprotein families include HipA homologs, luciferase genes, peptidases,and others.

A nonorthologous gene displacement is a nonorthologous gene from onespecies that can substitute for a referenced gene function in adifferent species. Substitution includes, for example, being able toperform substantially the same or a similar function in the species oforigin compared to the referenced function in the different species.Although generally, a nonorthologous gene displacement will beidentifiable as structurally related to a known gene encoding thereferenced function, less structurally related but functionally similargenes and their corresponding gene products nevertheless will still fallwithin the meaning of the term as it is used herein. Functionalsimilarity requires, for example, at least some structural similarity inthe active site or binding region of a nonorthologous gene productcompared to a gene encoding the function sought to be substituted.Therefore, a nonorthologous gene includes, for example, a paralog or anunrelated gene.

Therefore, in identifying and constructing the non-naturally occurringmicrobial organisms of the invention having alkene biosyntheticcapability, those skilled in the art will understand with applying theteaching and guidance provided herein to a particular species that theidentification of metabolic modifications can include identification andinclusion or inactivation of orthologs. To the extent that paralogsand/or nonorthologous gene displacements are present in the referencedmicroorganism that encode an enzyme catalyzing a similar orsubstantially similar metabolic reaction, those skilled in the art alsocan utilize these evolutionally related genes.

Orthologs, paralogs and nonorthologous gene displacements can bedetermined by methods well known to those skilled in the art. Forexample, inspection of nucleic acid or amino acid sequences for twopolypeptides will reveal sequence identity and similarities between thecompared sequences. Based on such similarities, one skilled in the artcan determine if the similarity is sufficiently high to indicate theproteins are related through evolution from a common ancestor.Algorithms well known to those skilled in the art, such as Align, BLAST,Clustal W and others compare and determine a raw sequence similarity oridentity, and also determine the presence or significance of gaps in thesequence which can be assigned a weight or score. Such algorithms alsoare known in the art and are similarly applicable for determiningnucleotide sequence similarity or identity. Parameters for sufficientsimilarity to determine relatedness are computed based on well knownmethods for calculating statistical similarity, or the chance of findinga similar match in a random polypeptide, and the significance of thematch determined. A computer comparison of two or more sequences can, ifdesired, also be optimized visually by those skilled in the art. Relatedgene products or proteins can be expected to have a high similarity, forexample, 25% to 100% sequence identity. Proteins that are unrelated canhave an identity which is essentially the same as would be expected tooccur by chance, if a database of sufficient size is scanned (about 5%).Sequences between 5% and 24% may or may not represent sufficienthomology to conclude that the compared sequences are related. Additionalstatistical analysis to determine the significance of such matches giventhe size of the data set can be carried out to determine the relevanceof these sequences.

Exemplary parameters for determining relatedness of two or moresequences using the BLAST algorithm, for example, can be as set forthbelow. Briefly, amino acid sequence alignments can be performed usingBLASTP version 2.0.8 (Jan. 5, 1999) and the following parameters:Matrix: 0 BLOSUM62; gap open: 11; gap extension: 1; x_dropoff: 50;expect: 10.0; wordsize: 3; filter: on. Nucleic acid sequence alignmentscan be performed using BLASTN version 2.0.6 (Sep. 16, 1998) and thefollowing parameters: Match: 1; mismatch: −2; gap open: 5; gapextension: 2; x_dropoff: 50; expect: 10.0; wordsize: 11; filter: off.Those skilled in the art will know what modifications can be made to theabove parameters to either increase or decrease the stringency of thecomparison, for example, and determine the relatedness of two or moresequences.

In some embodiments, the invention provides non-naturally occurringmicrobial organisms containing an alkene pathway having at least oneexogenous nucleic acid encoding an alkene pathway enzyme expressed in asufficient amount to convert an alcohol to an alkene as depicted inFIG. 1. In some aspects of the invention, the microbial organismcomprises an alkene pathway selected from: (1) an alcohol kinase and aphosphate lyase; (2) a diphosphokinase and a diphosphate lyase; and (3)an alcohol kinase, an alkyl phosphate kinase and a diphosphate lyase. Insome aspects of the invention, the microbial organism converts analcohol of Formula (I)

to an alkene of Formula (II)

wherein R¹, R², R³, and R⁴ are each independently (a) hydrogen, cyano,halo, or nitro; (b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, or heterocyclyl, eachoptionally substituted with one or more substituents Q; or (c)—C(O)R^(1a), —C(O)OR^(1a), —C(O)NR^(1b)R^(1c), —C(NR^(1a))NR^(1b)R^(1c),—OR^(1a), —OC(O)R^(1a), —OC(O)OR^(1a), —OC(O)NR^(1b)R^(1c),—OC(═NR^(1a))NR^(1b)R^(1c), —OS(O)R^(1a), —OS(O)₂R^(1a),—OS(O)NR^(1b)R^(1c), —OS(O)₂NR^(1b)R^(1c), —NR^(1b)R^(1c),—NR^(1a)C(O)R^(1d), —NR^(1a)C(O)OR^(1d), —NR^(1a)C(O)NR^(1b)R^(1c),—NR^(1a)C(═NR^(1d))NR^(1b)R^(1c), —NR^(1a)S(O)R^(1d),—NR^(1a)S(O)₂R^(1d), —NR^(1a)S(O)NR^(1b)R^(1c),—NR^(1a)S(O)₂NR^(1b)R^(1c), —SR^(1a), —S(O)R^(1a), —S(O)₂R^(1a),—S(O)NR^(1b)R^(1c), or —S(O)₂NR^(1b)R^(1c); wherein each R^(1a), R^(1b),R^(1c), and R^(1d) is independently hydrogen, C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, orheterocyclyl; or R^(1a) and R^(1c) together with the C and N atoms towhich they are attached form heterocyclyl; or R^(1b) and R^(1c) togetherwith the N atom to which they are attached form heterocyclyl; whereineach Q is independently selected from (a) oxo, cyano, halo, and nitro;(b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl,C₇₋₁₅ aralkyl, heteroaryl, and heterocyclyl, each of which is furtheroptionally substituted with one or more, in one embodiment, one, two,three, or four, substituents Q^(a); and (c) —C(O)R^(a), —C(O)OR^(a),—C(O)NR^(b)R^(c), —C(NR^(a))NR^(b)R^(c), —OR^(a), —OC(O)R^(a),—OC(O)OR^(a), —OC(O)NR^(b)R^(c), —OC(═NR^(a))NR^(b)R^(c), —OS(O)R^(a),—OS(O)₂R^(a), —OS(O)NR^(b)R^(c), —OS(O)₂NR^(b)R^(c), —NR^(b)R^(c),—NR^(a)C(O)R^(d), —NR^(a)C(O)OR^(d), —NR^(a)C(O)NR^(b)R^(c),—NR^(a)C(═NR^(d))NR^(b)R^(c), —NR^(a)S(O)R^(d), —NR^(a)S(O)₂R^(d),—NR^(a)S(O)NR^(b)R^(c), —NR^(a)S(O)₂NR^(b)R^(c), —SR^(a), —S(O)R^(a),—S(O)₂R^(a), —S(O)NR^(b)R^(c), and —S(O)₂NR^(b)R^(c), wherein eachR^(a), R^(b), R^(c), and R^(d) is independently (i) hydrogen; (ii) C₁₋₆alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅aralkyl, heteroaryl, or heterocyclyl, each optionally substituted withone or more, in one embodiment, one, two, three, or four, substituentsQ^(a); or (iii) R^(b) and R^(c) together with the N atom to which theyare attached form heterocyclyl, optionally substituted with one or more,in one embodiment, one, two, three, or four, substituents Q^(a); whereineach Q^(a) is independently selected from the group consisting of (a)oxo, cyano, halo, and nitro; (b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, andheterocyclyl; and (c) —C(O)R^(e), —C(O)OR^(e), —C(O)NR^(f)R^(g),—C(NR^(e))NR^(f)R^(g), —OR^(e), —OC(O)R^(e), —OC(O)OR^(e),—OC(O)NR^(f)R^(g), —OC(═NR^(e))NR^(f)R^(g), —OS(O)R^(e), —OS(O)₂R^(e),—OS(O)NR^(f)R^(g), —OS(O)₂NR^(f)R^(g), —NR^(f)R^(g), —NR^(e)C(O)R^(h),—NR^(e)C(O)OR^(f), —NR^(e)C(O)NR^(f)R^(g), —NR^(e)C(═NR^(h))NR^(f)R^(g),—NR^(e)S(O)R^(h), —NR^(e)S(O)₂R^(h), —NR^(e)S(O)NR^(f)R^(g),—NR^(e)S(O)₂NR^(f)R^(g), —SR^(e), —S(O)R^(e), —S(O)₂R^(e),—S(O)NR^(f)R^(g), and —S(O)₂NR^(f)R^(g); wherein each R^(e), R^(f),R^(g), and R^(h) is independently (i) hydrogen; (ii) C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl,heteroaryl, or heterocyclyl; or (iii) R^(f) and R^(g) together with theN atom to which they are attached form heterocyclyl. It is alsounderstood that R¹, R², R³, and R⁴ are each independently same betweenthe alcohol and the alkene. In otherwords, the R¹ of the alcohol is thesame as the R¹ of the alkene, the R² of the alcohol is the same as theR² of the alkene, the R³ of the alcohol is the same as the R³ of thealkene and the R⁴ of the alcohol is the same as the R⁴ of the alkene.

The term “alkyl” refers to a linear or branched saturated monovalenthydrocarbon radical, wherein the alkyl may optionally be substitutedwith one or more substituents Q as described herein. For example, C₁₋₆alkyl refers to a linear saturated monovalent hydrocarbon radical of 1to 6 carbon atoms or a branched saturated monovalent hydrocarbon radicalof 3 to 6 carbon atoms. In certain embodiments, the alkyl is a linearsaturated monovalent hydrocarbon radical that has 1 to 20 (C₁₋₂₀), 1 to15 (C₁₋₁₅), 1 to 10 (C₁₋₁₀), or 1 to 6 (C₁₋₆) carbon atoms, or branchedsaturated monovalent hydrocarbon radical of 3 to 20 (C₃₋₂₀), 3 to 15(C₃₋₁₅), 3 to 10 (C₃₋₁₀), or 3 to 6 (C₃₋₆) carbon atoms. As used herein,linear C₁₋₆ and branched C₃₋₆ alkyl groups are also referred as “loweralkyl.” Examples of alkyl groups include, but are not limited to,methyl, ethyl, propyl (including all isomeric forms), n-propyl,isopropyl, butyl (including all isomeric forms), n-butyl, isobutyl,sec-butyl, t-butyl, pentyl (including all isomeric forms), and hexyl(including all isomeric forms).

The term “alkenyl” refers to a linear or branched monovalent hydrocarbonradical, which contains one or more, in one embodiment, one to five, inanother embodiment, one, carbon-carbon double bond(s). The alkenyl maybe optionally substituted with one or more substituents Q as describedherein. The term “alkenyl” embraces radicals having a “cis” or “trans”configuration or a mixture thereof, or alternatively, a “Z” or “E”configuration or a mixture thereof, as appreciated by those of ordinaryskill in the art. For example, C₂₋₆ alkenyl refers to a linearunsaturated monovalent hydrocarbon radical of 2 to 6 carbon atoms or abranched unsaturated monovalent hydrocarbon radical of 3 to 6 carbonatoms. In certain embodiments, the alkenyl is a linear monovalenthydrocarbon radical of 2 to 20 (C₂₋₂₀), 2 to 15 (C₂₋₁₅), 2 to 10(C₂₋₁₀), or 2 to 6 (C₂₋₆) carbon atoms, or a branched monovalenthydrocarbon radical of 3 to 20 (C₃₋₂₀), 3 to 15 (C₃₋₁₅), 3 to 10(C₃₋₁₀), or 3 to 6 (C₃₋₆) carbon atoms. Examples of alkenyl groupsinclude, but are not limited to, ethenyl, propen-1-yl, propen-2-yl,allyl, butenyl, and 4-methylbutenyl.

The term “alkynyl” refers to a linear or branched monovalent hydrocarbonradical, which contains one or more, in one embodiment, one to five, inanother embodiment, one, carbon-carbon triple bond(s). The alkynyl maybe optionally substituted with one or more substituents Q as describedherein. For example, C₂₋₆ alkynyl refers to a linear unsaturatedmonovalent hydrocarbon radical of 2 to 6 carbon atoms or a branchedunsaturated monovalent hydrocarbon radical of 3 to 6 carbon atoms. Incertain embodiments, the alkynyl is a linear monovalent hydrocarbonradical of 2 to 20 (C₂₋₂₀), 2 to 15 (C₂₋₁₅), 2 to 10 (C₂₋₁₀), or 2 to 6(C₂₋₆) carbon atoms, or a branched monovalent hydrocarbon radical of 3to 20 (C₃₋₂₀), 3 to 15 (C₃₋₁₅), 3 to 10 (C₃₋₁₀), or 3 to 6 (C₃₋₆) carbonatoms. Examples of alkynyl groups include, but are not limited to,ethynyl (—C≡CH), propynyl (including all isomeric forms, e.g.,1-propynyl (—C≡CCH₃) and propargyl (—CH₂C≡CH)), butynyl (including allisomeric forms, e.g., 1-butyn-1-yl and 2-butyn-1-yl), pentynyl(including all isomeric forms, e.g., 1-pentyn-1-yl and1-methyl-2-butyn-1-yl), and hexynyl (including all isomeric forms, e.g.,1-hexyn-1-yl).

The term “cycloalkyl” refers to a cyclic monovalent hydrocarbon radical,which may be optionally substituted with one or more substituents Q asdescribed herein. In one embodiment, cycloalkyl groups may be saturatedor unsaturated but non-aromatic, and/or bridged, and/or non-bridged,and/or fused bicyclic groups. In certain embodiments, the cycloalkyl hasfrom 3 to 20 (C₃₋₂₀), from 3 to 15 (C₃₋₁₅), from 3 to 10 (C₃₋₁₀), orfrom 3 to 7 (C₃₋₇) carbon atoms. Examples of cycloalkyl groups include,but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclopentenyl, cyclohexyl, cyclohexenyl, cyclohexadienyl, cycloheptyl,cycloheptenyl, bicyclo[2.1.1]hexyl, bicyclo[2.2.1]heptyl, decalinyl, andadamantyl.

The term “aryl” refers to a monovalent monocyclic aromatic group and/ormonovalent polycyclic aromatic group that contain at least one aromaticcarbon ring. In certain embodiments, the aryl has from 6 to 20 (C₆₋₂₀),from 6 to 15 (C₆₋₁₅), or from 6 to 10 (C₆₋₁₀) ring atoms. Examples ofaryl groups include, but are not limited to, phenyl, naphthyl,fluorenyl, azulenyl, anthryl, phenanthryl, pyrenyl, biphenyl, andterphenyl. Aryl also refers to bicyclic or tricyclic carbon rings, whereone of the rings is aromatic and the others of which may be saturated,partially unsaturated, or aromatic, for example, dihydronaphthyl,indenyl, indanyl, or tetrahydronaphthyl (tetralinyl). In certainembodiments, aryl may be optionally substituted with one or moresubstituents Q as described herein.

The term “aralkyl” or “arylalkyl” refers to a monovalent alkyl groupsubstituted with one or more aryl groups. In certain embodiments, thearalkyl has from 7 to 30 (C₇₋₃₀), from 7 to 20 (C₇₋₂₀), or from 7 to 16(C₇₋₁₆) carbon atoms. Examples of aralkyl groups include, but are notlimited to, benzyl, 2-phenylethyl, and 3-phenylpropyl. In certainembodiments, aralkyl are optionally substituted with one or moresubstituents Q as described herein.

The term “heteroaryl” refers to a monovalent monocyclic aromatic groupor monovalent polycyclic aromatic group that contain at least onearomatic ring, wherein at least one aromatic ring contains one or moreheteroatoms independently selected from O, S, and N in the ring.Heteroaryl groups are bonded to the rest of a molecule through thearomatic ring. Each ring of a heteroaryl group can contain one or two Oatoms, one or two S atoms, and/or one to four N atoms, provided that thetotal number of heteroatoms in each ring is four or less and each ringcontains at least one carbon atom. In certain embodiments, theheteroaryl has from 5 to 20, from 5 to 15, or from 5 to 10 ring atoms.Examples of monocyclic heteroaryl groups include, but are not limitedto, furanyl, imidazolyl, isothiazolyl, isoxazolyl, oxadiazolyl,oxadiazolyl, oxazolyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridyl,pyrimidinyl, pyrrolyl, thiadiazolyl, thiazolyl, thienyl, tetrazolyl,triazinyl, and triazolyl. Examples of bicyclic heteroaryl groupsinclude, but are not limited to, benzofuranyl, benzimidazolyl,benzoisoxazolyl, benzopyranyl, benzothiadiazolyl, benzothiazolyl,benzothienyl, benzotriazolyl, benzoxazolyl, furopyridyl,imidazopyridinyl, imidazothiazolyl, indolizinyl, indolyl, indazolyl,isobenzofuranyl, isobenzothienyl, isoindolyl, isoquinolinyl,isothiazolyl, naphthyridinyl, oxazolopyridinyl, phthalazinyl,pteridinyl, purinyl, pyridopyridyl, pyrrolopyridyl, quinolinyl,quinoxalinyl, quinazolinyl, thiadiazolopyrimidyl, and thienopyridyl.Examples of tricyclic heteroaryl groups include, but are not limited to,acridinyl, benzindolyl, carbazolyl, dibenzofuranyl, perimidinyl,phenanthrolinyl, phenanthridinyl, phenarsazinyl, phenazinyl,phenothiazinyl, phenoxazinyl, and xanthenyl. In certain embodiments,heteroaryl may also be optionally substituted with one or moresubstituents Q as described herein.

The term “heterocyclyl” or “heterocyclic” refers to a monovalentmonocyclic non-aromatic ring system or monovalent polycyclic ring systemthat contains at least one non-aromatic ring, wherein one or more of thenon-aromatic ring atoms are heteroatoms independently selected from O,S, and N; and the remaining ring atoms are carbon atoms. In certainembodiments, the heterocyclyl or heterocyclic group has from 3 to 20,from 3 to 15, from 3 to 10, from 3 to 8, from 4 to 7, or from 5 to 6ring atoms. Heterocyclyl groups are bonded to the rest of a moleculethrough the non-aromatic ring. In certain embodiments, the heterocyclylis a monocyclic, bicyclic, tricyclic, or tetracyclic ring system, whichmay be fused or bridged, and in which nitrogen or sulfur atoms may beoptionally oxidized, nitrogen atoms may be optionally quaternized, andsome rings may be partially or fully saturated, or aromatic. Theheterocyclyl may be attached to the main structure at any heteroatom orcarbon atom which results in the creation of a stable compound. Examplesof such heterocyclic groups include, but are not limited to, azepinyl,benzodioxanyl, benzodioxolyl, benzofuranonyl, benzopyranonyl,benzopyranyl, benzotetrahydrofuranyl, benzotetrahydrothienyl,benzothiopyranyl, benzoxazinyl, β-carbolinyl, chromanyl, chromonyl,cinnolinyl, coumarinyl, decahydroisoquinolinyl, dihydrobenzisothiazinyl,dihydrobenzisoxazinyl, dihydrofuryl, dihydroisoindolyl, dihydropyranyl,dihydropyrazolyl, dihydropyrazinyl, dihydropyridinyl,dihydropyrimidinyl, dihydropyrrolyl, dioxolanyl, 1,4-dithianyl,furanonyl, imidazolidinyl, imidazolinyl, indolinyl,isobenzotetrahydrofuranyl, isobenzotetrahydrothienyl, isochromanyl,isocoumarinyl, isoindolinyl, isothiazolidinyl, isoxazolidinyl,morpholinyl, octahydroindolyl, octahydroisoindolyl, oxazolidinonyl,oxazolidinyl, oxiranyl, piperazinyl, piperidinyl, 4-piperidonyl,pyrazolidinyl, pyrazolinyl, pyrrolidinyl, pyrrolinyl, quinuclidinyl,tetrahydrofuryl, tetrahydroisoquinolinyl, tetrahydropyranyl,tetrahydrothienyl, thiamorpholinyl, thiazolidinyl, tetrahydroquinolinyl,and 1,3,5-trithianyl. In certain embodiments, heterocyclic may also beoptionally substituted with one or more substituents Q as describedherein.

The term “halogen”, “halide” or “halo” refers to fluorine, chlorine,bromine, and/or iodine.

The term “optionally substituted” is intended to mean that a group orsubstituent, such as an alkyl, alkylene, heteroalkylene, alkenyl,alkenylene, heteroalkenylene, alkynyl, alkynylene, cycloalkyl,cycloalkylene, aryl, arylene, aralkyl, heteroaryl, heteroarylene,heterocyclyl, or heterocyclylene group, may be substituted with one ormore substituents Q, each of which is independently selected from, e.g.,(a) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl,C₇₋₁₅ aralkyl, heteroaryl, and heterocyclyl, each of which is furtheroptionally substituted with one or more, in one embodiment, one, two,three, or four, substituents Q^(a); and (b) oxo (═O), halo, cyano (—CN),nitro (—NO₂), —C(O)R^(a), —C(O)OR^(a), —C(O)NR^(b)R^(c),—C(NR^(a))NR^(b)R^(c), —OR^(a), —OC(O)R^(a), —OC(O)OR^(a),—OC(O)NR^(b)R^(c), —OC(═NR^(a))NR^(b)R^(c), —OS(O)R^(a), —OS(O)₂R^(a),—OS(O)NR^(b)R^(c), —OS(O)₂NR^(b)R^(c), —NR^(b)R^(c), —NR^(a)C(O)R^(d),—NR^(a)C(O)OR^(d), —NR^(a)C(O)NR^(b)R^(c), —NR^(a)C(═NR^(d))NR^(b)R^(c),—NR^(a)S(O)R^(d), —NR^(a)S(O)₂R^(d), —NR^(a)S(O)NR^(b)R^(c),—NR^(a)S(O)₂NR^(b)R^(c), —SR^(a), —S(O)R^(a), —S(O)₂R^(a),—S(O)NR^(b)R^(c), and —S(O)₂NR^(b)R^(c), wherein each R^(a), R^(b),R^(c), and R^(d) is independently (i) hydrogen; (ii) C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl,heteroaryl, or heterocyclyl, each optionally substituted with one ormore, in one embodiment, one, two, three, or four, substituents Q^(a);or (iii) R^(b) and R^(c) together with the N atom to which they areattached form heteroaryl or heterocyclyl, optionally substituted withone or more, in one embodiment, one, two, three, or four, substituentsQ^(a). As used herein, all groups that can be substituted are“optionally substituted,” unless otherwise specified.

In one embodiment, each Q^(a) is independently selected from the groupconsisting of (a) oxo, cyano, halo, and nitro; and (b) C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl,heteroaryl, and heterocyclyl; and (c) —C(O)R^(e), —C(O)OR^(e),—C(O)NR^(f)R^(g), —C(NR^(e))NR^(f)R^(g), —OR^(e), —OC(O)R^(e),—OC(O)OR^(e), —OC(O)NR^(f)R^(g), —OC(═NR^(e))NR^(f)R^(g), —OS(O)R^(e),—OS(O)₂R^(e), —OS(O)NR^(f)R^(g), —OS(O)₂NR^(f)R^(g), —NR^(f)R^(g),—NR^(e)C(O)R^(h), —NR^(e)C(O)OR^(h), —NR^(e)C(O)NR^(f)R^(g),—NR^(e)C(═NR^(h))NR^(f)R^(g), —NR^(e)S(O)R^(h), —NR^(e)S(O)₂R^(h),—NR^(e)S(O)NR^(f)R^(g), —NR^(e)S(O)₂NR^(f)R^(g), —SR^(e), —S(O)R^(e),—S(O)₂R^(e), —S(O)NR^(f)R^(g), and —S(O)₂NR^(f)R^(g); wherein eachR^(e), R^(f), R^(g), and R^(h) is independently (i) hydrogen; (ii) C₁₋₆alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅aralkyl, heteroaryl, or heterocyclyl; or (iii) R^(f) and R^(g) togetherwith the N atom to which they are attached form heteroaryl orheterocyclyl.

FIG. 1 shows pathways for converting an alcohol to an alkene via aphosphate or diphosphate intermediate. In step A, an alcohol isactivated to an alkyl phosphate by a kinase. The alkyl phosphate is thenfurther activated to an alkyl diphosphate (Step D) or converted to analkene by a phosphate lyase or alkene synthase (step B). Alternately,the alcohol is directly converted to the alkyl diphosphate intermediateby a diphosphokinse (step C). The release of diphosphate from alkyldiphosphate by an alkene synthase or diphosphate lyase yields an alkene.Exemplary alcohol precursors and alkene products are listed in the tablebelow.

Alcohol Alkene Ethanol Ethylene n-Propanol Propylene IsopropanolPropylene n-Butanol But-1-ene Isobutanol Isobutylene Tert-butanolIsobutylene Butan-2-ol But-1-ene or but-2-ene Pentan-1-ol Pent-1-ene3-methylbutan-1-ol 3-methylbut-1-ene Pentan-2-ol Pent-2-ene orpent-2-ene Pentan-3-ol Pent-2-ene 2-Methylbutan-1-ol 2-methylbut-1-ene3-Methylbutan-2-ol 3-Methylbut-1-ene 2-Methylbutan-2-ol2-Methylbut-1-ene or 2-Methylbut-2-ene 3-Methylbut-3-en-1-ol Isoprene2-Methylbut-3-en-2-ol Isoprene 2-Methylbut-3-en-2-ol3-Methylbuta-1,2-diene 2-Methylbut-3-en-1-ol Isoprene3-Methylbut-3-en-2-ol Isoprene But-3-en-1-ol 1,3-Butadiene But-3-en-2-ol1,3-Butadiene 1-Phenylethanol Styrene 2-Phenylethanol StyreneDimethylallyl alcohol Isoprene But-2-en-1-ol 1,3-Butadiene

Accordingly, in some aspects, the invention provides a non-naturallyoccurring microbial organism containing an alkene pathway having atleast one exogenous nucleic acid encoding an alkene pathway enzymeexpressed in a sufficient amount to convert an alcohol to an alkene asdepicted in the table above. In some aspects of the invention, themicrobial organism comprises an alkene pathway selected from: (1) analcohol kinase and a phosphate lyase; (2) a diphosphokinase and adiphosphate lyase; and (3) an alcohol kinase, an alkyl phosphate kinaseand a diphosphate lyase. In some aspects, the microbial organism of theinvention converts ethanol to ethylene, n-propanol to propylene,isopropanol to propylene, n-butanol to but-1-ene, isobutanol toisobutylene, tert-butanol to isobutylene, butan-2-ol to but-1-ene orbut-2-ene, pentan-1-ol to pent-1-ene, 3-methylbutan-1-ol to3-methylbut-1-ene, pentan-2-ol to pent-2-ene, pental-3-ol to pent-2-ene,2-methylbutan-1-ol to 2-methylbut-1-ene, 3-methylbutan-2-ol to3-methylbut-1-ene, 2-methylbutan-2-ol to 2-methylbut-1-ene or2-methylbut-2-ene, 3-methylbut-3-en-1-ol to isoprene,2-methylbut-3-en-2-ol to isoprene, 2-methylbut-3-en-2-ol to3-methylbuta-1,2-diene, 2-methylbut-3-en-1-ol to isoprene,3-methylbut-3-en-2-ol to isoprene, but-3-en-1-ol to 1,3-butadiene,but-3-en-2-ol to 1,3-butadiene, 1-phenylethanol to styrene,2-phenylethanol to styrene, dimethylallyl alcohol to isoprene, orbut-2-en-1-ol to 1,3-butadiene.

In some embodiments of the invention, the non-naturally occurringmicrobial organism comprises two or three exogenous nucleic acids eachencoding an alkene pathway enzyme. For example, two exogenous nucleicacids can encode an alcohol kinase and a phosphate lyase, oralternatively a diphosphokinase and a diphosphate lyase. In some aspectsof the invention, non-naturally occurring microbial organism can includethree exogenous nucleic acids encoding an alcohol kinase, an alkylphosphate kinase and a diphosphate lyase. The invention also providesthat the at least one exogenous nucleic acid can be a heterologousnucleic acid. The invention still further provides that thenon-naturally occurring microbial organism can be in a substantiallyanaerobic culture medium.

In an additional embodiment, the invention provides a non-naturallyoccurring microbial organism having an alkene pathway, wherein thenon-naturally occurring microbial organism comprises at least oneexogenous nucleic acid encoding an enzyme or protein that converts asubstrate to a product selected from the group consisting of an alcoholto an alkyl phosphate, an alcohol to an alkyl diphosphate, an alkylphosphate to an alkyl diphosphate, an alkyl phosphate to an alkene or analkyl diphosphate to an alkene. One skilled in the art will understandthat these are merely exemplary and that any of the substrate-productpairs disclosed herein suitable to produce a desired product and forwhich an appropriate activity is available for the conversion of thesubstrate to the product can be readily determined by one skilled in theart based on the teachings herein. Thus, the invention provides anon-naturally occurring microbial organism containing at least oneexogenous nucleic acid encoding an enzyme or protein, where the enzymeor protein converts the substrates and products of an alkene pathway,such as that shown in FIG. 1.

While generally described herein as a microbial organism that containsan alkene pathway, it is understood that the invention additionallyprovides a non-naturally occurring microbial organism comprising atleast one exogenous nucleic acid encoding an alkene pathway enzymeexpressed in a sufficient amount to produce an intermediate of an alkenepathway. For example, as disclosed herein, an alkene pathway isexemplified in FIG. 1. Therefore, in addition to a microbial organismcontaining an alkene pathway that produces alkene, the inventionadditionally provides a non-naturally occurring microbial organismcomprising at least one exogenous nucleic acid encoding an alkenepathway enzyme, where the microbial organism produces an alkene pathwayintermediate, for example, an alkyl phosphate or an alkyl diphosphate.

It is understood that any of the pathways disclosed herein, as describedin the Examples and exemplified in the Figures, including the pathwaysof FIG. 1, can be utilized to generate a non-naturally occurringmicrobial organism that produces any pathway intermediate or product, asdesired. As disclosed herein, such a microbial organism that produces anintermediate can be used in combination with another microbial organismexpressing downstream pathway enzymes to produce a desired product.However, it is understood that a non-naturally occurring microbialorganism that produces an alkene pathway intermediate can be utilized toproduce the intermediate as a desired product.

The invention is described herein with general reference to themetabolic reaction, reactant or product thereof, or with specificreference to one or more nucleic acids or genes encoding an enzymeassociated with or catalyzing, or a protein associated with, thereferenced metabolic reaction, reactant or product. Unless otherwiseexpressly stated herein, those skilled in the art will understand thatreference to a reaction also constitutes reference to the reactants andproducts of the reaction. Similarly, unless otherwise expressly statedherein, reference to a reactant or product also references the reaction,and reference to any of these metabolic constituents also references thegene or genes encoding the enzymes that catalyze or proteins involved inthe referenced reaction, reactant or product. Likewise, given the wellknown fields of metabolic biochemistry, enzymology and genomics,reference herein to a gene or encoding nucleic acid also constitutes areference to the corresponding encoded enzyme and the reaction itcatalyzes or a protein associated with the reaction as well as thereactants and products of the reaction.

The non-naturally occurring microbial organisms of the invention can beproduced by introducing expressible nucleic acids encoding one or moreof the enzymes or proteins participating in one or more alkenebiosynthetic pathways. Depending on the host microbial organism chosenfor biosynthesis, nucleic acids for some or all of a particular alkenebiosynthetic pathway can be expressed. For example, if a chosen host isdeficient in one or more enzymes or proteins for a desired biosyntheticpathway, then expressible nucleic acids for the deficient enzyme(s) orprotein(s) are introduced into the host for subsequent exogenousexpression. Alternatively, if the chosen host exhibits endogenousexpression of some pathway genes, but is deficient in others, then anencoding nucleic acid is needed for the deficient enzyme(s) orprotein(s) to achieve alkene biosynthesis. Thus, a non-naturallyoccurring microbial organism of the invention can be produced byintroducing exogenous enzyme or protein activities to obtain a desiredbiosynthetic pathway or a desired biosynthetic pathway can be obtainedby introducing one or more exogenous enzyme or protein activities that,together with one or more endogenous enzymes or proteins, produces adesired product such as alkene.

Host microbial organisms can be selected from, and the non-naturallyoccurring microbial organisms generated in, for example, bacteria,yeast, fungus or any of a variety of other microorganisms applicable tofermentation processes. Exemplary bacteria include species selected fromEscherichia coli, Klebsiella oxytoca, Anaerobiospirillumsucciniciproducens, Actinobacillus succinogenes, Mannheimiasucciniciproducens, Rhizobium etli, Bacillus subtilis, Corynebacteriumglutamicum, Gluconobacter oxydans, Zymomonas mobilis, Lactococcuslactis, Lactobacillus plantarum, Streptomyces coelicolor, Clostridiumacetobutylicum, Pseudomonas fluorescens, and Pseudomonas putida.Exemplary yeasts or fungi include species selected from Saccharomycescerevisiae, Schizosaccharomyces pombe, Kluyveromyces lactis,Kluyveromyces marxianus, Aspergillus terreus, Aspergillus niger, Pichiapastoris, Rhizopus arrhizus, Rhizobus oryzae, Yarrowia lipolytica, andthe like. E. coli is a particularly useful host organism since it is awell characterized microbial organism suitable for genetic engineering.Other particularly useful host organisms include yeast such asSaccharomyces cerevisiae. It is understood that any suitable microbialhost organism can be used to introduce metabolic and/or geneticmodifications to produce a desired product.

Depending on the alkene biosynthetic pathway constituents of a selectedhost microbial organism, the non-naturally occurring microbial organismsof the invention will include at least one exogenously expressed alkenepathway-encoding nucleic acid and up to all encoding nucleic acids forone or more alkene biosynthetic pathways. For example, alkenebiosynthesis can be established in a host deficient in a pathway enzymeor protein through exogenous expression of the corresponding encodingnucleic acid. In a host deficient in all enzymes or proteins of analkene pathway, exogenous expression of all enzyme or proteins in thepathway can be included, although it is understood that all enzymes orproteins of a pathway can be expressed even if the host contains atleast one of the pathway enzymes or proteins. For example, exogenousexpression of all enzymes or proteins in a pathway for production ofalkene can be included, such as an alcohol kinase and a phosphate lyase,or alternatively a diphosephokinase and a diphosphate lyase, oralternatively an alcohol kinase, an alkyl phosphate kinase and adiphosphate lyase.

Given the teachings and guidance provided herein, those skilled in theart will understand that the number of encoding nucleic acids tointroduce in an expressible form will, at least, parallel the alkenepathway deficiencies of the selected host microbial organism. Therefore,a non-naturally occurring microbial organism of the invention can haveone, two or three up to all nucleic acids encoding the enzymes orproteins constituting an alkene biosynthetic pathway disclosed herein.In some embodiments, the non-naturally occurring microbial organismsalso can include other genetic modifications that facilitate or optimizealkene biosynthesis or that confer other useful functions onto the hostmicrobial organism. One such other functionality can include, forexample, augmentation of the synthesis of one or more of the alkenepathway precursors such as an alcohol disclosed herein.

Generally, a host microbial organism is selected such that it producesthe precursor of an alkene pathway, either as a naturally producedmolecule or as an engineered product that either provides de novoproduction of a desired precursor or increased production of a precursornaturally produced by the host microbial organism. For example, ethanolis produced naturally in a host organism such as E. coli. A hostorganism can be engineered to increase production of a precursor, asdisclosed herein. In addition, a microbial organism that has beenengineered to produce a desired precursor can be used as a host organismand further engineered to express enzymes or proteins of an alkenepathway.

In some embodiments, a non-naturally occurring microbial organism of theinvention is generated from a host that contains the enzymaticcapability to synthesize alkene. In this specific embodiment it can beuseful to increase the synthesis or accumulation of an alkene pathwayproduct to, for example, drive alkene pathway reactions toward alkeneproduction. Increased synthesis or accumulation can be accomplished by,for example, overexpression of nucleic acids encoding one or more of theabove-described alkene pathway enzymes or proteins. Overexpression ofthe enzyme or enzymes and/or protein or proteins of the alkene pathwaycan occur, for example, through exogenous expression of the endogenousgene or genes, or through exogenous expression of the heterologous geneor genes. Therefore, naturally occurring organisms can be readilygenerated to be non-naturally occurring microbial organisms of theinvention, for example, producing alkene, through overexpression of one,two, or three, that is, up to all nucleic acids encoding alkenebiosynthetic pathway enzymes or proteins. In addition, a non-naturallyoccurring organism can be generated by mutagenesis of an endogenous genethat results in an increase in activity of an enzyme in the alkenebiosynthetic pathway.

In particularly useful embodiments, exogenous expression of the encodingnucleic acids is employed. Exogenous expression confers the ability tocustom tailor the expression and/or regulatory elements to the host andapplication to achieve a desired expression level that is controlled bythe user. However, endogenous expression also can be utilized in otherembodiments such as by removing a negative regulatory effector orinduction of the gene's promoter when linked to an inducible promoter orother regulatory element. Thus, an endogenous gene having a naturallyoccurring inducible promoter can be up-regulated by providing theappropriate inducing agent, or the regulatory region of an endogenousgene can be engineered to incorporate an inducible regulatory element,thereby allowing the regulation of increased expression of an endogenousgene at a desired time. Similarly, an inducible promoter can be includedas a regulatory element for an exogenous gene introduced into anon-naturally occurring microbial organism.

It is understood that, in methods of the invention, any of the one ormore exogenous nucleic acids can be introduced into a microbial organismto produce a non-naturally occurring microbial organism of theinvention. The nucleic acids can be introduced so as to confer, forexample, an alkene biosynthetic pathway onto the microbial organism.Alternatively, encoding nucleic acids can be introduced to produce anintermediate microbial organism having the biosynthetic capability tocatalyze some of the required reactions to confer alkene biosyntheticcapability. For example, a non-naturally occurring microbial organismhaving an alkene biosynthetic pathway can comprise at least twoexogenous nucleic acids encoding desired enzymes or proteins, such asthe combination of an alcohol kinase and a phosphate lyase, oralternatively a diphosphokinase and a diphosphate lyase, and the like.Thus, it is understood that any combination of two or more enzymes orproteins of a biosynthetic pathway can be included in a non-naturallyoccurring microbial organism of the invention. Similarly, it isunderstood that any combination of three or more enzymes or proteins ofa biosynthetic pathway can be included in a non-naturally occurringmicrobial organism of the invention, for example, an alcohol kinase, analkyl phosphate kinase and a diphosphate lyase, and so forth, asdesired, so long as the combination of enzymes and/or proteins of thedesired biosynthetic pathway results in production of the correspondingdesired product.

In addition to the biosynthesis of alkene as described herein, thenon-naturally occurring microbial organisms and methods of the inventionalso can be utilized in various combinations with each other and withother microbial organisms and methods well known in the art to achieveproduct biosynthesis by other routes. For example, one alternative toproduce alkene other than use of the alkene producers is throughaddition of another microbial organism capable of converting an alkenepathway intermediate to alkene. One such procedure includes, forexample, the fermentation of a microbial organism that produces analkene pathway intermediate. The alkene pathway intermediate can then beused as a substrate for a second microbial organism that converts thealkene pathway intermediate to alkene. The alkene pathway intermediatecan be added directly to another culture of the second organism or theoriginal culture of the alkene pathway intermediate producers can bedepleted of these microbial organisms by, for example, cell separation,and then subsequent addition of the second organism to the fermentationbroth can be utilized to produce the final product without intermediatepurification steps.

In other embodiments, the non-naturally occurring microbial organismsand methods of the invention can be assembled in a wide variety ofsubpathways to achieve biosynthesis of, for example, alkene. In theseembodiments, biosynthetic pathways for a desired product of theinvention can be segregated into different microbial organisms, and thedifferent microbial organisms can be co-cultured to produce the finalproduct. In such a biosynthetic scheme, the product of one microbialorganism is the substrate for a second microbial organism until thefinal product is synthesized. For example, the biosynthesis of alkenecan be accomplished by constructing a microbial organism that containsbiosynthetic pathways for conversion of one pathway intermediate toanother pathway intermediate or the product. Alternatively, alkene alsocan be biosynthetically produced from microbial organisms throughco-culture or co-fermentation using two organisms in the same vessel,where the first microbial organism produces an alkyl phosphate or alkyldiphosphate intermediate and the second microbial organism converts theintermediate to alkene.

Given the teachings and guidance provided herein, those skilled in theart will understand that a wide variety of combinations and permutationsexist for the non-naturally occurring microbial organisms and methods ofthe invention together with other microbial organisms, with theco-culture of other non-naturally occurring microbial organisms havingsubpathways and with combinations of other chemical and/or biochemicalprocedures well known in the art to produce alkene.

Sources of encoding nucleic acids for an alkene pathway enzyme orprotein can include, for example, any species where the encoded geneproduct is capable of catalyzing the referenced reaction. Such speciesinclude both prokaryotic and eukaryotic organisms including, but notlimited to, bacteria, including archaea and eubacteria, and eukaryotes,including yeast, plant, insect, animal, and mammal, including human.Exemplary species for such sources include, for example, Escherichiacoli, Abies grandis, Acetobacter pasteurians, Acinetobacter sp. strainM-1, Arabidopsis thaliana, Arabidopsis thaliana col, Aspergillus terreusNIH2624, Bacillus amyloliquefaciens, Bacillus cereus, Bos Taurus,Bradyrhizobium japonicum USDA110, Burkholderia phymatum, Burkholderiaxenovorans, Clostridium acetobutylicum, Clostridium beijerinckii,Clostridium beijerinckii NRRL B593, Clostridium botulinum, Clostridiumkluyveri DSM 555, Clostridium saccharoperbutylacetonicum, Comamonas sp.CNB-1, Cucumis sativus, Cupriavidus taiwanensis, Enterococcus faecalis,Escherichia coli C, Escherichia coli K12, Escherichia coli W,Geobacillus thermoglucosidasius, Homo sapiens, Klebsiella pneumonia,Kluyveromyces lactis, Lactococcus lactis, Malus×domestica, Mesorhizobiumloti, Methanocaldococcus jannaschii, Methanosarcina mazei, Mycobacteriumtuberculosis, Mycoplasma pneumoniae M129, Neurospora crassa, Oryctolaguscuniculus, Picea abies, Populus alba, Populus tremula×Populus alba,Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas sp. CF600,Pueraria Montana, Pyrococcus furiosus, Ralstonia eutropha, Ralstoniaeutropha H16, Ralstonia metallidurans, Rattus norvegicus, Rhodococcusruber, Saccharomyces cerevisiae, Salmonella enteric, Solanumlycopersicum, Staphylococcus aureus, Streptococcus pneumonia,Streptomyces sp. ACT-1, Thermoanaerobacter brockii HTD4, Thermotogamaritime MSB8, Thermus thermophilus, Zea mays, Zoogloea ramigera,Zymomonas mobilis, as well as other exemplary species disclosed hereinor available as source organisms for corresponding genes. However, withthe complete genome sequence available for now more than 550 species(with more than half of these available on public databases such as theNCBI), including 395 microorganism genomes and a variety of yeast,fungi, plant, and mammalian genomes, the identification of genesencoding the requisite alkene biosynthetic activity for one or moregenes in related or distant species, including for example, homologues,orthologs, paralogs and nonorthologous gene displacements of knowngenes, and the interchange of genetic alterations between organisms isroutine and well known in the art. Accordingly, the metabolicalterations allowing biosynthesis of alkene described herein withreference to a particular organism such as E. coli can be readilyapplied to other microorganisms, including prokaryotic and eukaryoticorganisms alike. Given the teachings and guidance provided herein, thoseskilled in the art will know that a metabolic alteration exemplified inone organism can be applied equally to other organisms.

In some instances, such as when an alternative alkene biosyntheticpathway exists in an unrelated species, alkene biosynthesis can beconferred onto the host species by, for example, exogenous expression ofa paralog or paralogs from the unrelated species that catalyzes asimilar, yet non-identical metabolic reaction to replace the referencedreaction. Because certain differences among metabolic networks existbetween different organisms, those skilled in the art will understandthat the actual gene usage between different organisms may differ.However, given the teachings and guidance provided herein, those skilledin the art also will understand that the teachings and methods of theinvention can be applied to all microbial organisms using the cognatemetabolic alterations to those exemplified herein to construct amicrobial organism in a species of interest that will synthesize alkene.

Methods for constructing and testing the expression levels of anon-naturally occurring alkene-producing host can be performed, forexample, by recombinant and detection methods well known in the art.Such methods can be found described in, for example, Sambrook et al.,Molecular Cloning: A Laboratory Manual, Third Ed., Cold Spring HarborLaboratory, New York (2001); and Ausubel et al., Current Protocols inMolecular Biology, John Wiley and Sons, Baltimore, Md. (1999).

Exogenous nucleic acid sequences involved in a pathway for production ofalkene can be introduced stably or transiently into a host cell usingtechniques well known in the art including, but not limited to,conjugation, electroporation, chemical transformation, transduction,transfection, and ultrasound transformation. For exogenous expression inE. coli or other prokaryotic cells, some nucleic acid sequences in thegenes or cDNAs of eukaryotic nucleic acids can encode targeting signalssuch as an N-terminal mitochondrial or other targeting signal, which canbe removed before transformation into prokaryotic host cells, ifdesired. For example, removal of a mitochondrial leader sequence led toincreased expression in E. coli (Hoffmeister et al., J. Biol. Chem.280:4329-4338 (2005)). For exogenous expression in yeast or othereukaryotic cells, genes can be expressed in the cytosol without theaddition of leader sequence, or can be targeted to mitochondrion orother organelles, or targeted for secretion, by the addition of asuitable targeting sequence such as a mitochondrial targeting orsecretion signal suitable for the host cells. Thus, it is understoodthat appropriate modifications to a nucleic acid sequence to remove orinclude a targeting sequence can be incorporated into an exogenousnucleic acid sequence to impart desirable properties. Furthermore, genescan be subjected to codon optimization with techniques well known in theart to achieve optimized expression of the proteins.

An expression vector or vectors can be constructed to include one ormore alkene biosynthetic pathway encoding nucleic acids as exemplifiedherein operably linked to expression control sequences functional in thehost organism. Expression vectors applicable for use in the microbialhost organisms of the invention include, for example, plasmids, phagevectors, viral vectors, episomes and artificial chromosomes, includingvectors and selection sequences or markers operable for stableintegration into a host chromosome. Additionally, the expression vectorscan include one or more selectable marker genes and appropriateexpression control sequences. Selectable marker genes also can beincluded that, for example, provide resistance to antibiotics or toxins,complement auxotrophic deficiencies, or supply critical nutrients not inthe culture media. Expression control sequences can include constitutiveand inducible promoters, transcription enhancers, transcriptionterminators, and the like which are well known in the art. When two ormore exogenous encoding nucleic acids are to be co-expressed, bothnucleic acids can be inserted, for example, into a single expressionvector or in separate expression vectors. For single vector expression,the encoding nucleic acids can be operationally linked to one commonexpression control sequence or linked to different expression controlsequences, such as one inducible promoter and one constitutive promoter.The transformation of exogenous nucleic acid sequences involved in ametabolic or synthetic pathway can be confirmed using methods well knownin the art. Such methods include, for example, nucleic acid analysissuch as Northern blots or polymerase chain reaction (PCR) amplificationof mRNA, or immunoblotting for expression of gene products, or othersuitable analytical methods to test the expression of an introducednucleic acid sequence or its corresponding gene product. It isunderstood by those skilled in the art that the exogenous nucleic acidis expressed in a sufficient amount to produce the desired product, andit is further understood that expression levels can be optimized toobtain sufficient expression using methods well known in the art and asdisclosed herein.

The invention additionally provides methods of using the microbialorganisms disclosed herein to produce an alkene, by culturing anon-naturally occurring microbial organism containing an alkene pathwayas described herein under conditions and for a sufficient period of timeto produce an alkene. In some aspects of the method, the microbialorganism used in the method can produce an alkene, wherein the alkene isa compound of Formula (II)

wherein R¹, R², R³, and R⁴ are each independently (a) hydrogen, cyano,halo, or nitro; (b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, or heterocyclyl, eachoptionally substituted with one or more substituents Q; or (c)C(O)R^(1a), —C(O)OR^(1a), —C(O)NR^(1b)R^(1c), —C(NR^(1a))NR^(1b)R^(1c),—OR^(1a), —OC(O)R^(1a), —OC(O)OR^(1a), —OC(O)NR^(1b)R^(1c),—OC(═NR^(1a))NR^(1b)R^(1c), —OS(O)R^(1a), —OS(O)₂R^(1a),—OS(O)NR^(1b)R^(1c), —OS(O)₂NR^(1b)R^(1c), —NR^(1b)R^(1c),—NR^(1a)C(O)R^(1d), —NR^(1a)C(O)OR^(1d), —NR^(1a)C(O)NR^(1b)R^(1c),—NR^(1a)C(═NR^(1d))NR^(1b)R^(1c), —NR^(1a)S(O)R^(1d),—NR^(1a)S(O)₂R^(1d), —NR^(1a)S(O)NR^(1b)R^(1c),—NR^(1a)S(O)₂NR^(1b)R^(1c), —SR^(1a), —S(O)R^(1a), —S(O)₂R^(1a),—S(O)NR^(1b)R^(1c), or —S(O)₂NR^(1b)R^(1c); wherein each R^(1a), R^(1b),R^(1c), and R^(1d) is independently hydrogen, C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, orheterocyclyl; or R^(1a) and R^(1c) together with the C and N atoms towhich they are attached form heterocyclyl; or R^(1b) and R^(1c) togetherwith the N atom to which they are attached form heterocyclyl; whereineach Q is independently selected from (a) oxo, cyano, halo, and nitro;(b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl,C₇₋₁₅ aralkyl, heteroaryl, and heterocyclyl, each of which is furtheroptionally substituted with one or more, in one embodiment, one, two,three, or four, substituents Q^(a); and (c) —C(O)R^(a), —C(O)OR^(a),—C(O)NR^(b)R^(c), —C(NR^(a))NR^(b)R^(c), —OR^(a), —OC(O)R^(a),—OC(O)OR^(a), —OC(O)NR^(b)R^(c), —OC(═NR^(a))NR^(b)R^(c), —OS(O)R^(a),—OS(O)₂R^(a), —OS(O)NR^(b)R^(c), —OS(O)₂NR^(b)R^(c), —NR^(b)R^(c),—NR^(a)C(O)R^(d), —NR^(a)C(O)OR^(d), —NR^(a)C(O)NR^(b)R^(c),—NR^(a)C(═NR^(d))NR^(b)R^(c), —NR^(a)S(O)R^(d), —NR^(a)S(O)₂R^(d),—NR^(a)S(O)NR^(b)R^(c), —NR^(a)S(O)₂NR^(b)R^(c), —SR^(a), —S(O)R^(a),—S(O)₂R^(a), —S(O)NR^(b)R^(c), and —S(O)₂NR^(b)R^(c), wherein eachR^(a), R^(b), R^(c), and R^(d) is independently (i) hydrogen; (ii) C₁₋₆alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅aralkyl, heteroaryl, or heterocyclyl, each optionally substituted withone or more, in one embodiment, one, two, three, or four, substituentsQ^(a); or (iii) R^(b) and R^(c) together with the N atom to which theyare attached form heterocyclyl, optionally substituted with one or more,in one embodiment, one, two, three, or four, substituents Q^(a); whereineach Q^(a) is independently selected from the group consisting of (a)oxo, cyano, halo, and nitro; (b) C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl,C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl, heteroaryl, andheterocyclyl; and (c) —C(O)R^(e), —C(O)OR^(e), —C(O)NR^(f)R^(g),—C(NR^(e))NR^(f)R^(g), —OR^(e), —OC(O)R^(e), —OC(O)OR^(e),—OC(O)NR^(f)R^(g), —OC(═NR^(e))NR^(f)R^(g), —OS(O)R^(e), —OS(O)₂R^(e),—OS(O)NR^(f)R^(g), —OS(O)₂NR^(f)R^(g), —NR^(f)R^(g), —NR^(e)C(O)R^(h),—NR^(e)C(O)OR^(f), —NR^(e)C(O)NR^(f)R^(g), —NR^(e)C(═NR^(h))NR^(f)R^(g),—NR^(e)S(O)R^(h), —NR^(e)S(O)₂R^(h), —NR^(e)S(O)NR^(f)R^(g),—NR^(e)S(O)₂NR^(f)R^(g), —SR^(e), —S(O)R^(e), —S(O)₂R^(e),—S(O)NR^(f)R^(g), and —S(O)₂NR^(f)R^(g); wherein each R^(e), R^(f),R^(g), and R^(h) is independently (i) hydrogen; (ii) C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₇ cycloalkyl, C₆₋₁₄ aryl, C₇₋₁₅ aralkyl,heteroaryl, or heterocyclyl; or (iii) R^(f) and R^(g) together with theN atom to which they are attached form heterocyclyl.

In some aspects, the microbial organism used in the method disclosedherein can produce an alkene, wherein the alkene is a compound selectedfrom, but are not limited to, Ethylene, Propylene, Propylene, But-1-ene,Isobutylene, Isobutylene, But-1-ene, but-2-ene, Pent-1-ene,3-methylbut-1-ene, Pent-2-ene, 2-methylbut-1-ene, 3-Methylbut-1-ene,2-Methylbut-1-ene, 2-Methylbut-2-ene, Isoprene, 3-Methylbuta-1,2-diene,1,3-Butadiene and Styrene.

In some embodiments the alkene product is gaseous and has limitedsolubility in the culture broth under the conditions of the process.This is advantageous, as removal of the gas from the reaction vessel candrive the alkene-forming pathway reactions in the forward direction.

Elevated temperature can further limit solubility of the alkeneproducts. A desirable property of the microorganism containing thealkene-producing pathway is the ability to grow at elevatedtemperatures. Exemplary thermophilic and heat-tolerant organisms includeThermus aquaticus, bacteria of the genus Clostridium and microorganismsof the genera Thermotoga and Aquifex. A desired property of thealkene-producing pathway enzymes is the ability to catalyze the desiredreactions at elevated temperatures. Such enzymes can be isolated fromthermophilic organisms or can be obtained by mutagenizing availableenzymes and screening or selecting for increased activity underincreased temperature conditions.

Suitable purification and/or assays to test for the production of analkene can be performed using well known methods. Suitable replicatessuch as triplicate cultures can be grown for each engineered strain tobe tested. For example, product and byproduct formation in theengineered production host can be monitored. The final product andintermediates, and other organic compounds, can be analyzed by methodssuch as HPLC (High Performance Liquid Chromatography), GC-MS (GasChromatography-Mass Spectroscopy) and LC-MS (Liquid Chromatography-MassSpectroscopy) or other suitable analytical methods using routineprocedures well known in the art. The release of product in thefermentation broth can also be tested with the culture supernatant.Byproducts and residual glucose can be quantified by HPLC using, forexample, a refractive index detector for glucose and alcohols, and a UVdetector for organic acids (Lin et al., Biotechnol. Bioeng. 90:775-779(2005)), or other suitable assay and detection methods well known in theart. The individual enzyme or protein activities from the exogenous DNAsequences can also be assayed using methods well known in the art.Gaseous samples can be analyzed by gas chromatography (GC) coupled witha flame ionization detector, and further by GC-MS.

The alkene can be separated from other components in the culture using avariety of methods well known in the art. Such separation methodsinclude, for example, extraction procedures as well as methods thatinclude continuous liquid-liquid extraction, pervaporation, membranefiltration, membrane separation, reverse osmosis, electrodialysis,distillation, crystallization, centrifugation, extractive filtration,ion exchange chromatography, size exclusion chromatography, adsorptionchromatography, and ultrafiltration. All of the above methods are wellknown in the art.

Any of the non-naturally occurring microbial organisms described hereincan be cultured to produce and/or secrete the biosynthetic products ofthe invention. For example, the alkene producers can be cultured for thebiosynthetic production of alkene.

For the production of alkene, the recombinant strains are cultured in amedium with carbon source and other essential nutrients. It is sometimesdesirable and can be highly desirable to maintain anaerobic conditionsin the fermenter to reduce the cost of the overall process. Suchconditions can be obtained, for example, by first sparging the mediumwith nitrogen and then sealing the flasks with a septum and crimp-cap.For strains where growth is not observed anaerobically, microaerobic orsubstantially anaerobic conditions can be applied by perforating theseptum with a small hole for limited aeration. Exemplary anaerobicconditions have been described previously and are well-known in the art.Exemplary aerobic and anaerobic conditions are described, for example,in United State publication 2009/0047719, filed Aug. 10, 2007.Fermentations can be performed in a batch, fed-batch or continuousmanner, as disclosed herein.

If desired, the pH of the medium can be maintained at a desired pH, inparticular neutral pH, such as a pH of around 7 by addition of a base,such as NaOH or other bases, or acid, as needed to maintain the culturemedium at a desirable pH. The growth rate can be determined by measuringoptical density using a spectrophotometer (600 nm), and the glucoseuptake rate by monitoring carbon source depletion over time.

The growth medium can include, for example, any carbohydrate sourcewhich can supply a source of carbon to the non-naturally occurringmicroorganism. Such sources include, for example, sugars such asglucose, xylose, arabinose, galactose, mannose, fructose, sucrose andstarch. Other sources of carbohydrate include, for example, renewablefeedstocks and biomass. Exemplary types of biomasses that can be used asfeedstocks in the methods of the invention include cellulosic biomass,hemicellulosic biomass and lignin feedstocks or portions of feedstocks.Such biomass feedstocks contain, for example, carbohydrate substratesuseful as carbon sources such as glucose, xylose, arabinose, galactose,mannose, fructose and starch. Given the teachings and guidance providedherein, those skilled in the art will understand that renewablefeedstocks and biomass other than those exemplified above also can beused for culturing the microbial organisms of the invention for theproduction of alkene.

In addition to renewable feedstocks such as those exemplified above, thealkene microbial organisms of the invention also can be modified forgrowth on syngas as its source of carbon. In this specific embodiment,one or more proteins or enzymes are expressed in the alkene producingorganisms to provide a metabolic pathway for utilization of syngas orother gaseous carbon source.

Synthesis gas, also known as syngas or producer gas, is the majorproduct of gasification of coal and of carbonaceous materials such asbiomass materials, including agricultural crops and residues. Syngas isa mixture primarily of H₂ and CO and can be obtained from thegasification of any organic feedstock, including but not limited tocoal, coal oil, natural gas, biomass, and waste organic matter.Gasification is generally carried out under a high fuel to oxygen ratio.Although largely H₂ and CO, syngas can also include CO₂ and other gasesin smaller quantities. Thus, synthesis gas provides a cost effectivesource of gaseous carbon such as CO and, additionally, CO₂.

The Wood-Ljungdahl pathway catalyzes the conversion of CO and H₂ toacetyl-CoA and other products such as acetate. Organisms capable ofutilizing CO and syngas also generally have the capability of utilizingCO₂ and CO₂/H₂ mixtures through the same basic set of enzymes andtransformations encompassed by the Wood-Ljungdahl pathway. H₂-dependentconversion of CO₂ to acetate by microorganisms was recognized longbefore it was revealed that CO also could be used by the same organismsand that the same pathways were involved. Many acetogens have been shownto grow in the presence of CO₂ and produce compounds such as acetate aslong as hydrogen is present to supply the necessary reducing equivalents(see for example, Drake, Acetogenesis, pp. 3-60 Chapman and Hall, NewYork, (1994)). This can be summarized by the following equation:2CO₂+4H₂ +nADP+nPi→CH₃COOH+2H₂O+nATP

Hence, non-naturally occurring microorganisms possessing theWood-Ljungdahl pathway can utilize CO₂ and H₂ mixtures as well for theproduction of acetyl-CoA and other desired products.

The Wood-Ljungdahl pathway is well known in the art and consists of 12reactions which can be separated into two branches: (1) methyl branchand (2) carbonyl branch. The methyl branch converts syngas tomethyl-tetrahydrofolate (methyl-THF) whereas the carbonyl branchconverts methyl-THF to acetyl-CoA. The reactions in the methyl branchare catalyzed in order by the following enzymes or proteins: ferredoxinoxidoreductase, formate dehydrogenase, formyltetrahydrofolatesynthetase, methenyltetrahydrofolate cyclodehydratase,methylenetetrahydrofolate dehydrogenase and methylenetetrahydrofolatereductase. The reactions in the carbonyl branch are catalyzed in orderby the following enzymes or proteins: methyltetrahydrofolate:corrinoidprotein methyltransferase (for example, AcsE), corrinoid iron-sulfurprotein, nickel-protein assembly protein (for example, AcsF),ferredoxin, acetyl-CoA synthase, carbon monoxide dehydrogenase andnickel-protein assembly protein (for example, CooC). Following theteachings and guidance provided herein for introducing a sufficientnumber of encoding nucleic acids to generate an alkene pathway, thoseskilled in the art will understand that the same engineering design alsocan be performed with respect to introducing at least the nucleic acidsencoding the Wood-Ljungdahl enzymes or proteins absent in the hostorganism. Therefore, introduction of one or more encoding nucleic acidsinto the microbial organisms of the invention such that the modifiedorganism contains the complete Wood-Ljungdahl pathway will confer syngasutilization ability.

Additionally, the reductive (reverse) tricarboxylic acid cycle coupledwith carbon monoxide dehydrogenase and/or hydrogenase activities canalso be used for the conversion of CO, CO₂ and/or H₂ to acetyl-CoA andother products such as acetate. Organisms capable of fixing carbon viathe reductive TCA pathway can utilize one or more of the followingenzymes: ATP citrate-lyase, citrate lyase, aconitase, isocitratedehydrogenase, alpha-ketoglutarate:ferredoxin oxidoreductase,succinyl-CoA synthetase, succinyl-CoA transferase, fumarate reductase,fumarase, malate dehydrogenase, NAD(P)H:ferredoxin oxidoreductase,carbon monoxide dehydrogenase, and hydrogenase. Specifically, thereducing equivalents extracted from CO and/or H₂ by carbon monoxidedehydrogenase and hydrogenase are utilized to fix CO₂ via the reductiveTCA cycle into acetyl-CoA or acetate. Acetate can be converted toacetyl-CoA by enzymes such as acetyl-CoA transferase, acetatekinase/phosphotransacetylase, and acetyl-CoA synthetase. Acetyl-CoA canbe converted to the alkene precursors, glyceraldehyde-3-phosphate,phosphoenolpyruvate, and pyruvate, by pyruvate:ferredoxin oxidoreductaseand the enzymes of gluconeogenesis. Following the teachings and guidanceprovided herein for introducing a sufficient number of encoding nucleicacids to generate an alkene pathway, those skilled in the art willunderstand that the same engineering design also can be performed withrespect to introducing at least the nucleic acids encoding the reductiveTCA pathway enzymes or proteins absent in the host organism. Therefore,introduction of one or more encoding nucleic acids into the microbialorganisms of the invention such that the modified organism contains areductive TCA pathway can confer syngas utilization ability.

Accordingly, given the teachings and guidance provided herein, thoseskilled in the art will understand that a non-naturally occurringmicrobial organism can be produced that secretes the biosynthesizedcompounds of the invention when grown on a carbon source such as acarbohydrate. Such compounds include, for example, alkene and any of theintermediate metabolites in the alkene pathway. All that is required isto engineer in one or more of the required enzyme or protein activitiesto achieve biosynthesis of the desired compound or intermediateincluding, for example, inclusion of some or all of the alkenebiosynthetic pathways. Accordingly, the invention provides anon-naturally occurring microbial organism that produces and/or secretesalkene when grown on a carbohydrate or other carbon source and producesand/or secretes any of the intermediate metabolites shown in the alkenepathway when grown on a carbohydrate or other carbon source. The alkeneproducing microbial organisms of the invention can initiate synthesisfrom an intermediate, for example, an alkyl phosphate or an alkyldiphosphate.

The non-naturally occurring microbial organisms of the invention areconstructed using methods well known in the art as exemplified herein toexogenously express at least one nucleic acid encoding an alkene pathwayenzyme or protein in sufficient amounts to produce alkene. It isunderstood that the microbial organisms of the invention are culturedunder conditions sufficient to produce alkene. Following the teachingsand guidance provided herein, the non-naturally occurring microbialorganisms of the invention can achieve biosynthesis of alkene resultingin intracellular concentrations between about 0.1-200 mM or more.Generally, the intracellular concentration of alkene is between about3-150 mM, particularly between about 5-125 mM and more particularlybetween about 8-100 mM, including about 10 mM, 20 mM, 50 mM, 80 mM, ormore. Intracellular concentrations between and above each of theseexemplary ranges also can be achieved from the non-naturally occurringmicrobial organisms of the invention.

In some embodiments, culture conditions include anaerobic orsubstantially anaerobic growth or maintenance conditions. Exemplaryanaerobic conditions have been described previously and are well knownin the art. Exemplary anaerobic conditions for fermentation processesare described herein and are described, for example, in U.S. publication2009/0047719, filed Aug. 10, 2007. Any of these conditions can beemployed with the non-naturally occurring microbial organisms as well asother anaerobic conditions well known in the art. Under such anaerobicor substantially anaerobic conditions, the alkene producers cansynthesize alkene at intracellular concentrations of 5-10 mM or more aswell as all other concentrations exemplified herein. It is understoodthat, even though the above description refers to intracellularconcentrations, alkene producing microbial organisms can produce alkeneintracellularly and/or secrete the product into the culture medium.

In addition to the culturing and fermentation conditions disclosedherein, growth condition for achieving biosynthesis of alkene caninclude the addition of an osmoprotectant to the culturing conditions.In certain embodiments, the non-naturally occurring microbial organismsof the invention can be sustained, cultured or fermented as describedherein in the presence of an osmoprotectant. Briefly, an osmoprotectantrefers to a compound that acts as an osmolyte and helps a microbialorganism as described herein survive osmotic stress. Osmoprotectantsinclude, but are not limited to, betaines, amino acids, and the sugartrehalose. Non-limiting examples of such are glycine betaine, pralinebetaine, dimethylthetin, dimethylslfonioproprionate,3-dimethylsulfonio-2-methylproprionate, pipecolic acid,dimethylsulfonioacetate, choline, L-carnitine and ectoine. In oneaspect, the osmoprotectant is glycine betaine. It is understood to oneof ordinary skill in the art that the amount and type of osmoprotectantsuitable for protecting a microbial organism described herein fromosmotic stress will depend on the microbial organism used. The amount ofosmoprotectant in the culturing conditions can be, for example, no morethan about 0.1 mM, no more than about 0.5 mM, no more than about 1.0 mM,no more than about 1.5 mM, no more than about 2.0 mM, no more than about2.5 mM, no more than about 3.0 mM, no more than about 5.0 mM, no morethan about 7.0 mM, no more than about 10 mM, no more than about 50 mM,no more than about 100 mM or no more than about 500 mM.

In some embodiments, the carbon feedstock and other cellular uptakesources such as phosphate, ammonia, sulfate, chloride and other halogenscan be chosen to alter the isotopic distribution of the atoms present inan alkene or any alkene pathway intermediate. The various carbonfeedstock and other uptake sources enumerated above will be referred toherein, collectively, as “uptake sources.” Uptake sources can provideisotopic enrichment for any atom present in the product alkene or alkenepathway intermediate, or for side products generated in reactionsdiverging away from an alkene pathway. Isotopic enrichment can beachieved for any target atom including, for example, carbon, hydrogen,oxygen, nitrogen, sulfur, phosphorus, chloride or other halogens.

In some embodiments, the uptake sources can be selected to alter thecarbon-12, carbon-13, and carbon-14 ratios. In some embodiments, theuptake sources can be selected to alter the oxygen-16, oxygen-17, andoxygen-18 ratios. In some embodiments, the uptake sources can beselected to alter the hydrogen, deuterium, and tritium ratios. In someembodiments, the uptake sources can be selected to alter the nitrogen-14and nitrogen-15 ratios. In some embodiments, the uptake sources can beselected to alter the sulfur-32, sulfur-33, sulfur-34, and sulfur-35ratios. In some embodiments, the uptake sources can be selected to alterthe phosphorus-31, phosphorus-32, and phosphorus-33 ratios. In someembodiments, the uptake sources can be selected to alter thechlorine-35, chlorine-36, and chlorine-37 ratios.

In some embodiments, the isotopic ratio of a target atom can be variedto a desired ratio by selecting one or more uptake sources. An uptakesource can be derived from a natural source, as found in nature, or froma man-made source, and one skilled in the art can select a naturalsource, a man-made source, or a combination thereof, to achieve adesired isotopic ratio of a target atom. An example of a man-made uptakesource includes, for example, an uptake source that is at leastpartially derived from a chemical synthetic reaction. Such isotopicallyenriched uptake sources can be purchased commercially or prepared in thelaboratory and/or optionally mixed with a natural source of the uptakesource to achieve a desired isotopic ratio. In some embodiments, atarget atom isotopic ratio of an uptake source can be achieved byselecting a desired origin of the uptake source as found in nature. Forexample, as discussed herein, a natural source can be a biobased derivedfrom or synthesized by a biological organism or a source such aspetroleum-based products or the atmosphere. In some such embodiments, asource of carbon, for example, can be selected from a fossilfuel-derived carbon source, which can be relatively depleted ofcarbon-14, or an environmental or atmospheric carbon source, such asCO₂, which can possess a larger amount of carbon-14 than itspetroleum-derived counterpart.

The unstable carbon isotope carbon-14 or radiocarbon makes up forroughly 1 in 10¹² carbon atoms in the earth's atmosphere and has ahalf-life of about 5700 years. The stock of carbon is replenished in theupper atmosphere by a nuclear reaction involving cosmic rays andordinary nitrogen (¹⁴N). Fossil fuels contain no carbon-14, as itdecayed long ago. Burning of fossil fuels lowers the atmosphericcarbon-14 fraction, the so-called “Suess effect”.

Methods of determining the isotopic ratios of atoms in a compound arewell known to those skilled in the art. Isotopic enrichment is readilyassessed by mass spectrometry using techniques known in the art such asaccelerated mass spectrometry (AMS), Stable Isotope Ratio MassSpectrometry (SIRMS) and Site-Specific Natural Isotopic Fractionation byNuclear Magnetic Resonance (SNIF-NMR). Such mass spectral techniques canbe integrated with separation techniques such as liquid chromatography(LC), high performance liquid chromatography (HPLC) and/or gaschromatography, and the like.

In the case of carbon, ASTM D6866 was developed in the United States asa standardized analytical method for determining the biobased content ofsolid, liquid, and gaseous samples using radiocarbon dating by theAmerican Society for Testing and Materials (ASTM) International. Thestandard is based on the use of radiocarbon dating for the determinationof a product's biobased content. ASTM D6866 was first published in 2004,and the current active version of the standard is ASTM D6866-11(effective Apr. 1, 2011). Radiocarbon dating techniques are well knownto those skilled in the art, including those described herein.

The biobased content of a compound is estimated by the ratio ofcarbon-14 (¹⁴C) to carbon-12 (¹²C). Specifically, the Fraction Modern(Fm) is computed from the expression: Fm=(S−B)/(M−B), where B, S and Mrepresent the ¹⁴C/¹²C ratios of the blank, the sample and the modernreference, respectively. Fraction Modern is a measurement of thedeviation of the ¹⁴C/¹²C ratio of a sample from “Modern.” Modern isdefined as 95% of the radiocarbon concentration (in AD 1950) of NationalBureau of Standards (NBS) Oxalic Acid I (i.e., standard referencematerials (SRM) 4990b) normalized to δ¹³C_(VPDB)=−19 per mil (Olsson,The use of Oxalic acid as a Standard. in, Radiocarbon Variations andAbsolute Chronology, Nobel Symposium, 12th Proc., John Wiley & Sons, NewYork (1970)). Mass spectrometry results, for example, measured by ASM,are calculated using the internationally agreed upon definition of 0.95times the specific activity of NBS Oxalic Acid I (SRM 4990b) normalizedto δ¹³C_(VPDB)=−19 per mil. This is equivalent to an absolute (AD 1950)¹⁴C/¹²C ratio of 1.176±0.010×10⁻¹² (Karlen et al., Arkiv Geofysik,4:465-471 (1968)). The standard calculations take into account thedifferential uptake of one isotope with respect to another, for example,the preferential uptake in biological systems of C¹² over C¹³ over C¹⁴,and these corrections are reflected as a Fm corrected for δ¹³.

An oxalic acid standard (SRM 4990b or HOx 1) was made from a crop of1955 sugar beet. Although there were 1000 lbs made, this oxalic acidstandard is no longer commercially available. The Oxalic Acid IIstandard (HOx 2; N.I.S.T designation SRM 4990 C) was made from a crop of1977 French beet molasses. In the early 1980's, a group of 12laboratories measured the ratios of the two standards. The ratio of theactivity of Oxalic acid II to 1 is 1.2933±0.001 (the weighted mean). Theisotopic ratio of HOx II is −17.8 per mille. ASTM D6866-11 suggests useof the available Oxalic Acid II standard SRM 4990 C (Hox2) for themodern standard (see discussion of original vs. currently availableoxalic acid standards in Mann, Radiocarbon, 25(2):519-527 (1983)). AFm=0% represents the entire lack of carbon-14 atoms in a material, thusindicating a fossil (for example, petroleum based) carbon source. AFm=100%, after correction for the post-1950 injection of carbon-14 intothe atmosphere from nuclear bomb testing, indicates an entirely moderncarbon source. As described herein, such a “modern” source includesbiobased sources.

As described in ASTM D6866, the percent modern carbon (pMC) can begreater than 100% because of the continuing but diminishing effects ofthe 1950s nuclear testing programs, which resulted in a considerableenrichment of carbon-14 in the atmosphere as described in ASTM D6866-11.Because all sample carbon-14 activities are referenced to a “pre-bomb”standard, and because nearly all new biobased products are produced in apost-bomb environment, all pMC values (after correction for isotopicfraction) must be multiplied by 0.95 (as of 2010) to better reflect thetrue biobased content of the sample. A biobased content that is greaterthan 103% suggests that either an analytical error has occurred, or thatthe source of biobased carbon is more than several years old.

ASTM D6866 quantifies the biobased content relative to the material'stotal organic content and does not consider the inorganic carbon andother non-carbon containing substances present. For example, a productthat is 50% starch-based material and 50% water would be considered tohave a Biobased Content=100% (50% organic content that is 100% biobased)based on ASTM D6866. In another example, a product that is 50%starch-based material, 25% petroleum-based, and 25% water would have aBiobased Content=66.7% (75% organic content but only 50% of the productis biobased). In another example, a product that is 50% organic carbonand is a petroleum-based product would be considered to have a BiobasedContent=0% (50% organic carbon but from fossil sources). Thus, based onthe well known methods and known standards for determining the biobasedcontent of a compound or material, one skilled in the art can readilydetermine the biobased content and/or prepared downstream products thatutilize of the invention having a desired biobased content.

Applications of carbon-14 dating techniques to quantify bio-basedcontent of materials are known in the art (Currie et al., NuclearInstruments and Methods in Physics Research B, 172:281-287 (2000)). Forexample, carbon-14 dating has been used to quantify bio-based content interephthalate-containing materials (Colonna et al., Green Chemistry,13:2543-2548 (2011)). Notably, polypropylene terephthalate (PPT)polymers derived from renewable 1,3-propanediol and petroleum-derivedterephthalic acid resulted in Fm values near 30% (i.e., since 3/11 ofthe polymeric carbon derives from renewable 1,3-propanediol and 8/11from the fossil end member terephthalic acid) (Currie et al., supra,2000). In contrast, polybutylene terephthalate polymer derived from bothrenewable 1,4-butanediol and renewable terephthalic acid resulted inbio-based content exceeding 90% (Colonna et al., supra, 2011).

Accordingly, in some embodiments, the present invention provides analkene or an alkene pathway intermediate that has a carbon-12,carbon-13, and carbon-14 ratio that reflects an atmospheric carbon, alsoreferred to as environmental carbon, uptake source. For example, in someaspects the alkene or alkene pathway intermediate can have an Fm valueof at least 10%, at least 15%, at least 20%, at least 25%, at least 30%,at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, atleast 60%, at least 65%, at least 70%, at least 75%, at least 80%, atleast 85%, at least 90%, at least 95%, at least 98% or as much as 100%.In some such embodiments, the uptake source is CO₂. In some embodiments,the present invention provides an alkene or an alkene pathwayintermediate that has a carbon-12, carbon-13, and carbon-14 ratio thatreflects petroleum-based carbon uptake source. In this aspect, thealkene or alkene pathway intermediate can have an Fm value of less than95%, less than 90%, less than 85%, less than 80%, less than 75%, lessthan 70%, less than 65%, less than 60%, less than 55%, less than 50%,less than 45%, less than 40%, less than 35%, less than 30%, less than25%, less than 20%, less than 15%, less than 10%, less than 5%, lessthan 2% or less than 1%. In some embodiments, the present inventionprovides an alkene or an alkene pathway intermediate that has acarbon-12, carbon-13, and carbon-14 ratio that is obtained by acombination of an atmospheric carbon uptake source with apetroleum-based uptake source. Using such a combination of uptakesources is one way by which the carbon-12, carbon-13, and carbon-14ratio can be varied, and the respective ratios would reflect theproportions of the uptake sources.

Further, the present invention relates to the biologically producedalkene or alkene pathway intermediate as disclosed herein, and to theproducts derived therefrom, wherein the alkene or alkene pathwayintermediate has a carbon-12, carbon-13, and carbon-14 isotope ratio ofabout the same value as the CO₂ that occurs in the environment. Forexample, in some aspects the invention provides bioderived alkene or abioderived alkene intermediate having a carbon-12 versus carbon-13versus carbon-14 isotope ratio of about the same value as the CO₂ thatoccurs in the environment, or any of the other ratios disclosed herein.It is understood, as disclosed herein, that a product can have acarbon-12 versus carbon-13 versus carbon-14 isotope ratio of about thesame value as the CO₂ that occurs in the environment, or any of theratios disclosed herein, wherein the product is generated from abioderived alkene or a bioderived alkene pathway intermediate asdisclosed herein, wherein the bioderived product is chemically modifiedto generate a final product. Methods of chemically modifying abioderived product of alkene, or an intermediate thereof, to generate adesired product are well known to those skilled in the art, as describedherein. The invention further provides a plastic, a polymer, aco-polymer, a polymer intermediate, a resin, a rubber, or a fiber havinga carbon-12 versus carbon-13 versus carbon-14 isotope ratio of about thesame value as the CO₂ that occurs in the environment, wherein the aplastic, a polymer, a co-polymer, a polymer intermediate, a resin, arubber, or a fiber are generated directly from or in combination withbioderived alkene or a bioderived alkene pathway intermediate asdisclosed herein.

Alkenes include a variety chemicals as described herein, which can beused in commercial and industrial applications. For example, the alkenesdisclosed herein can be used as a raw material in the production of awide range of products including plastics, polymers, co-polymers,polymer intermediates, resins, rubbers, or fibers. Accordingly, in someembodiments, the invention provides biobased plastics, polymers,co-polymers, polymer intermediates, resins, rubbers, or fiberscomprising one or more bioderived alkene or bioderived alkene pathwayintermediate produced by a non-naturally occurring microorganism of theinvention or produced using a method disclosed herein.

As used herein, the term “bioderived” means derived from or synthesizedby a biological organism and can be considered a renewable resourcesince it can be generated by a biological organism. Such a biologicalorganism, in particular the microbial organisms of the inventiondisclosed herein, can utilize feedstock or biomass, such as, sugars orcarbohydrates obtained from an agricultural, plant, bacterial, or animalsource. Alternatively, the biological organism can utilize atmosphericcarbon. As used herein, the term “biobased” means a product as describedabove that is composed, in whole or in part, of a bioderived compound ofthe invention. A biobased or bioderived product is in contrast to apetroleum derived product, wherein such a product is derived from orsynthesized from petroleum or a petrochemical feedstock.

In some embodiments, the invention provides a plastic, a polymer, aco-polymer, a polymer intermediate, a resin, a rubber, or a fibercomprising a bioderived alkene or a bioderived alkene pathwayintermediate, wherein the bioderived alkene or bioderived alkene pathwayintermediate includes all or part of the alkene or alkene pathwayintermediate used in the production of the plastic, polymer, co-polymer,polymer intermediate, resin, rubber, or fiber. Thus, in some aspects,the invention provides a biobased plastic, polymer, co-polymer, polymerintermediate, resin, rubber, or fiber comprising at least 2%, at least3%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%,at least 30%, at least 35%, at least 40%, at least 50%, at least 60%, atleast 70%, at least 80%, at least 90%, at least 95%, at least 98% or100% bioderived alkene or bioderived alkene pathway intermediate asdisclosed herein. Additionally, in some aspects, the invention providesa biobased plastic, polymer, co-polymer, polymer intermediate, resin,rubber, or fiber wherein the alkene or alkene pathway intermediate usedin its production is a combination of bioderived and petroleum derivedalkene or alkene pathway intermediate. For example, a biobased plastic,polymer, co-polymer, polymer intermediate, resin, rubber, or fiber canbe produced using 50% bioderived alkene and 50% petroleum derived alkeneor other desired ratios such as 60%/40%, 70%/30%, 80%/20%, 90%/10%,95%/5%, 100%/0%, 40%/60%, 30%/70%, 20%/80%, 10%/90% ofbioderived/petroleum derived precursors, so long as at least a portionof the product comprises a bioderived product produced by the microbialorganisms disclosed herein. It is understood that methods for producingplastic, polymer, co-polymer, polymer intermediate, resin, rubber, orfiber using the bioderived alkene or bioderived alkene pathwayintermediate of the invention are well known in the art.

The culture conditions can include, for example, liquid cultureprocedures as well as fermentation and other large scale cultureprocedures. As described herein, particularly useful yields of thebiosynthetic products of the invention can be obtained under anaerobicor substantially anaerobic culture conditions.

As described herein, one exemplary growth condition for achievingbiosynthesis of alkene includes anaerobic culture or fermentationconditions. In certain embodiments, the non-naturally occurringmicrobial organisms of the invention can be sustained, cultured orfermented under anaerobic or substantially anaerobic conditions.Briefly, anaerobic conditions refers to an environment devoid of oxygen.Substantially anaerobic conditions include, for example, a culture,batch fermentation or continuous fermentation such that the dissolvedoxygen concentration in the medium remains between 0 and 10% ofsaturation. Substantially anaerobic conditions also includes growing orresting cells in liquid medium or on solid agar inside a sealed chambermaintained with an atmosphere of less than 1% oxygen. The percent ofoxygen can be maintained by, for example, sparging the culture with anN₂/CO₂ mixture or other suitable non-oxygen gas or gases.

The culture conditions described herein can be scaled up and growncontinuously for manufacturing of alkene. Exemplary growth proceduresinclude, for example, fed-batch fermentation and batch separation;fed-batch fermentation and continuous separation, or continuousfermentation and continuous separation. All of these processes are wellknown in the art. Fermentation procedures are particularly useful forthe biosynthetic production of commercial quantities of alkene.Generally, and as with non-continuous culture procedures, the continuousand/or near-continuous production of alkene will include culturing anon-naturally occurring alkene producing organism of the invention insufficient nutrients and medium to sustain and/or nearly sustain growthin an exponential phase. Continuous culture under such conditions caninclude, for example, growth for 1 day, 2, 3, 4, 5, 6 or 7 days or more.Additionally, continuous culture can include longer time periods of 1week, 2, 3, 4 or 5 or more weeks and up to several months.Alternatively, organisms of the invention can be cultured for hours, ifsuitable for a particular application. It is to be understood that thecontinuous and/or near-continuous culture conditions also can includeall time intervals in between these exemplary periods. It is furtherunderstood that the time of culturing the microbial organism of theinvention is for a sufficient period of time to produce a sufficientamount of product for a desired purpose.

Fermentation procedures are well known in the art. Briefly, fermentationfor the biosynthetic production of alkene can be utilized in, forexample, fed-batch fermentation and batch separation; fed-batchfermentation and continuous separation, or continuous fermentation andcontinuous separation. Examples of batch and continuous fermentationprocedures are well known in the art.

In addition to the above fermentation procedures using the alkeneproducers of the invention for continuous production of substantialquantities of alkene, the alkene producers also can be, for example,simultaneously subjected to chemical synthesis procedures to convert theproduct to other compounds or the product can be separated from thefermentation culture and sequentially subjected to chemical or enzymaticconversion to convert the product to other compounds, if desired.

To generate better producers, metabolic modeling can be utilized tooptimize growth conditions. Modeling can also be used to design geneknockouts that additionally optimize utilization of the pathway (see,for example, U.S. patent publications US 2002/0012939, US 2003/0224363,US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 andUS 2004/0009466, and U.S. Pat. No. 7,127,379). Modeling analysis allowsreliable predictions of the effects on cell growth of shifting themetabolism towards more efficient production of alkene.

One computational method for identifying and designing metabolicalterations favoring biosynthesis of a desired product is the OptKnockcomputational framework (Burgard et al., Biotechnol. Bioeng. 84:647-657(2003)). OptKnock is a metabolic modeling and simulation program thatsuggests gene deletion or disruption strategies that result ingenetically stable microorganisms which overproduce the target product.Specifically, the framework examines the complete metabolic and/orbiochemical network of a microorganism in order to suggest geneticmanipulations that force the desired biochemical to become an obligatorybyproduct of cell growth. By coupling biochemical production with cellgrowth through strategically placed gene deletions or other functionalgene disruption, the growth selection pressures imposed on theengineered strains after long periods of time in a bioreactor lead toimprovements in performance as a result of the compulsory growth-coupledbiochemical production. Lastly, when gene deletions are constructedthere is a negligible possibility of the designed strains reverting totheir wild-type states because the genes selected by OptKnock are to becompletely removed from the genome. Therefore, this computationalmethodology can be used to either identify alternative pathways thatlead to biosynthesis of a desired product or used in connection with thenon-naturally occurring microbial organisms for further optimization ofbiosynthesis of a desired product.

Briefly, OptKnock is a term used herein to refer to a computationalmethod and system for modeling cellular metabolism. The OptKnock programrelates to a framework of models and methods that incorporate particularconstraints into flux balance analysis (FBA) models. These constraintsinclude, for example, qualitative kinetic information, qualitativeregulatory information, and/or DNA microarray experimental data.OptKnock also computes solutions to various metabolic problems by, forexample, tightening the flux boundaries derived through flux balancemodels and subsequently probing the performance limits of metabolicnetworks in the presence of gene additions or deletions. OptKnockcomputational framework allows the construction of model formulationsthat allow an effective query of the performance limits of metabolicnetworks and provides methods for solving the resulting mixed-integerlinear programming problems. The metabolic modeling and simulationmethods referred to herein as OptKnock are described in, for example,U.S. publication 2002/0168654, filed Jan. 10, 2002, in InternationalPatent No. PCT/US02/00660, filed Jan. 10, 2002, and U.S. publication2009/0047719, filed Aug. 10, 2007.

Another computational method for identifying and designing metabolicalterations favoring biosynthetic production of a product is a metabolicmodeling and simulation system termed SimPheny®. This computationalmethod and system is described in, for example, U.S. publication2003/0233218, filed Jun. 14, 2002, and in International PatentApplication No. PCT/US03/18838, filed Jun. 13, 2003. SimPheny® is acomputational system that can be used to produce a network model insilico and to simulate the flux of mass, energy or charge through thechemical reactions of a biological system to define a solution spacethat contains any and all possible functionalities of the chemicalreactions in the system, thereby determining a range of allowedactivities for the biological system. This approach is referred to asconstraints-based modeling because the solution space is defined byconstraints such as the known stoichiometry of the included reactions aswell as reaction thermodynamic and capacity constraints associated withmaximum fluxes through reactions. The space defined by these constraintscan be interrogated to determine the phenotypic capabilities andbehavior of the biological system or of its biochemical components.

These computational approaches are consistent with biological realitiesbecause biological systems are flexible and can reach the same result inmany different ways. Biological systems are designed throughevolutionary mechanisms that have been restricted by fundamentalconstraints that all living systems must face. Therefore,constraints-based modeling strategy embraces these general realities.Further, the ability to continuously impose further restrictions on anetwork model via the tightening of constraints results in a reductionin the size of the solution space, thereby enhancing the precision withwhich physiological performance or phenotype can be predicted.

Given the teachings and guidance provided herein, those skilled in theart will be able to apply various computational frameworks for metabolicmodeling and simulation to design and implement biosynthesis of adesired compound in host microbial organisms. Such metabolic modelingand simulation methods include, for example, the computational systemsexemplified above as SimPheny® and OptKnock. For illustration of theinvention, some methods are described herein with reference to theOptKnock computation framework for modeling and simulation. Thoseskilled in the art will know how to apply the identification, design andimplementation of the metabolic alterations using OptKnock to any ofsuch other metabolic modeling and simulation computational frameworksand methods well known in the art.

The methods described above will provide one set of metabolic reactionsto disrupt. Elimination of each reaction within the set or metabolicmodification can result in a desired product as an obligatory productduring the growth phase of the organism. Because the reactions areknown, a solution to the bilevel OptKnock problem also will provide theassociated gene or genes encoding one or more enzymes that catalyze eachreaction within the set of reactions. Identification of a set ofreactions and their corresponding genes encoding the enzymesparticipating in each reaction is generally an automated process,accomplished through correlation of the reactions with a reactiondatabase having a relationship between enzymes and encoding genes.

Once identified, the set of reactions that are to be disrupted in orderto achieve production of a desired product are implemented in the targetcell or organism by functional disruption of at least one gene encodingeach metabolic reaction within the set. One particularly useful means toachieve functional disruption of the reaction set is by deletion of eachencoding gene. However, in some instances, it can be beneficial todisrupt the reaction by other genetic aberrations including, forexample, mutation, deletion of regulatory regions such as promoters orcis binding sites for regulatory factors, or by truncation of the codingsequence at any of a number of locations. These latter aberrations,resulting in less than total deletion of the gene set can be useful, forexample, when rapid assessments of the coupling of a product are desiredor when genetic reversion is less likely to occur.

To identify additional productive solutions to the above describedbilevel OptKnock problem which lead to further sets of reactions todisrupt or metabolic modifications that can result in the biosynthesis,including growth-coupled biosynthesis of a desired product, anoptimization method, termed integer cuts, can be implemented. Thismethod proceeds by iteratively solving the OptKnock problem exemplifiedabove with the incorporation of an additional constraint referred to asan integer cut at each iteration. Integer cut constraints effectivelyprevent the solution procedure from choosing the exact same set ofreactions identified in any previous iteration that obligatorily couplesproduct biosynthesis to growth. For example, if a previously identifiedgrowth-coupled metabolic modification specifies reactions 1, 2, and 3for disruption, then the following constraint prevents the samereactions from being simultaneously considered in subsequent solutions.The integer cut method is well known in the art and can be founddescribed in, for example, Burgard et al., Biotechnol. Prog. 17:791-797(2001). As with all methods described herein with reference to their usein combination with the OptKnock computational framework for metabolicmodeling and simulation, the integer cut method of reducing redundancyin iterative computational analysis also can be applied with othercomputational frameworks well known in the art including, for example,SimPheny®.

The methods exemplified herein allow the construction of cells andorganisms that biosynthetically produce a desired product, including theobligatory coupling of production of a target biochemical product togrowth of the cell or organism engineered to harbor the identifiedgenetic alterations. Therefore, the computational methods describedherein allow the identification and implementation of metabolicmodifications that are identified by an in silico method selected fromOptKnock or SimPheny®. The set of metabolic modifications can include,for example, addition of one or more biosynthetic pathway enzymes and/orfunctional disruption of one or more metabolic reactions including, forexample, disruption by gene deletion.

As discussed above, the OptKnock methodology was developed on thepremise that mutant microbial networks can be evolved towards theircomputationally predicted maximum-growth phenotypes when subjected tolong periods of growth selection. In other words, the approach leveragesan organism's ability to self-optimize under selective pressures. TheOptKnock framework allows for the exhaustive enumeration of genedeletion combinations that force a coupling between biochemicalproduction and cell growth based on network stoichiometry. Theidentification of optimal gene/reaction knockouts requires the solutionof a bilevel optimization problem that chooses the set of activereactions such that an optimal growth solution for the resulting networkoverproduces the biochemical of interest (Burgard et al., Biotechnol.Bioeng. 84:647-657 (2003)).

An in silico stoichiometric model of E. coli metabolism can be employedto identify essential genes for metabolic pathways as exemplifiedpreviously and described in, for example, U.S. patent publications US2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US2003/0059792, US 2002/0168654 and US 2004/0009466, and in U.S. Pat. No.7,127,379. As disclosed herein, the OptKnock mathematical framework canbe applied to pinpoint gene deletions leading to the growth-coupledproduction of a desired product. Further, the solution of the bilevelOptKnock problem provides only one set of deletions. To enumerate allmeaningful solutions, that is, all sets of knockouts leading togrowth-coupled production formation, an optimization technique, termedinteger cuts, can be implemented. This entails iteratively solving theOptKnock problem with the incorporation of an additional constraintreferred to as an integer cut at each iteration, as discussed above.

As disclosed herein, a nucleic acid encoding a desired activity of analkene pathway can be introduced into a host organism. In some cases, itcan be desirable to modify an activity of an alkene pathway enzyme orprotein to increase production of alkene. For example, known mutationsthat increase the activity of a protein or enzyme can be introduced intoan encoding nucleic acid molecule. Additionally, optimization methodscan be applied to increase the activity of an enzyme or protein and/ordecrease an inhibitory activity, for example, decrease the activity of anegative regulator.

One such optimization method is directed evolution. Directed evolutionis a powerful approach that involves the introduction of mutationstargeted to a specific gene in order to improve and/or alter theproperties of an enzyme. Improved and/or altered enzymes can beidentified through the development and implementation of sensitivehigh-throughput screening assays that allow the automated screening ofmany enzyme variants (for example, >10⁴). Iterative rounds ofmutagenesis and screening typically are performed to afford an enzymewith optimized properties. Computational algorithms that can help toidentify areas of the gene for mutagenesis also have been developed andcan significantly reduce the number of enzyme variants that need to begenerated and screened. Numerous directed evolution technologies havebeen developed (for reviews, see Hibbert et al., Biomol. Eng 22:11-19(2005); Huisman and Lalonde, In Biocatalysis in the pharmaceutical andbiotechnology industries pgs. 717-742 (2007), Patel (ed.), CRC Press;Otten and Quax. Biomol. Eng 22:1-9 (2005); and Sen et al., Appl Biochem.Biotechnol 143:212-223 (2007)) to be effective at creating diversevariant libraries, and these methods have been successfully applied tothe improvement of a wide range of properties across many enzymeclasses. Enzyme characteristics that have been improved and/or alteredby directed evolution technologies include, for example:selectivity/specificity, for conversion of non-natural substrates;temperature stability, for robust high temperature processing; pHstability, for bioprocessing under lower or higher pH conditions;substrate or product tolerance, so that high product titers can beachieved; binding (K_(m)), including broadening substrate binding toinclude non-natural substrates; inhibition (K_(i)), to remove inhibitionby products, substrates, or key intermediates; activity (kcat), toincreases enzymatic reaction rates to achieve desired flux; expressionlevels, to increase protein yields and overall pathway flux; oxygenstability, for operation of air sensitive enzymes under aerobicconditions; and anaerobic activity, for operation of an aerobic enzymein the absence of oxygen.

A number of exemplary methods have been developed for the mutagenesisand diversification of genes to target desired properties of specificenzymes. Such methods are well known to those skilled in the art. Any ofthese can be used to alter and/or optimize the activity of an alkenepathway enzyme or protein. Such methods include, but are not limited toEpPCR, which introduces random point mutations by reducing the fidelityof DNA polymerase in PCR reactions (Pritchard et al., J Theor. Biol.234:497-509 (2005)); Error-prone Rolling Circle Amplification (epRCA),which is similar to epPCR except a whole circular plasmid is used as thetemplate and random 6-mers with exonuclease resistant thiophosphatelinkages on the last 2 nucleotides are used to amplify the plasmidfollowed by transformation into cells in which the plasmid isre-circularized at tandem repeats (Fujii et al., Nucleic Acids Res.32:e145 (2004); and Fujii et al., Nat. Protoc. 1:2493-2497 (2006)); DNAor Family Shuffling, which typically involves digestion of two or morevariant genes with nucleases such as Dnase I or EndoV to generate a poolof random fragments that are reassembled by cycles of annealing andextension in the presence of DNA polymerase to create a library ofchimeric genes (Stemmer, Proc Natl Acad Sci USA 91:10747-10751 (1994);and Stemmer, Nature 370:389-391 (1994)); Staggered Extension (StEP),which entails template priming followed by repeated cycles of 2 step PCRwith denaturation and very short duration of annealing/extension (asshort as 5 sec) (Zhao et al., Nat. Biotechnol. 16:258-261 (1998));Random Priming Recombination (RPR), in which random sequence primers areused to generate many short DNA fragments complementary to differentsegments of the template (Shao et al., Nucleic Acids Res 26:681-683(1998)).

Additional methods include Heteroduplex Recombination, in whichlinearized plasmid DNA is used to form heteroduplexes that are repairedby mismatch repair (Volkov et al, Nucleic Acids Res. 27:e18 (1999); andVolkov et al., Methods Enzymol. 328:456-463 (2000)); RandomChimeragenesis on Transient Templates (RACHITT), which employs Dnase Ifragmentation and size fractionation of single stranded DNA (ssDNA)(Coco et al., Nat. Biotechnol. 19:354-359 (2001)); Recombined Extensionon Truncated templates (RETT), which entails template switching ofunidirectionally growing strands from primers in the presence ofunidirectional ssDNA fragments used as a pool of templates (Lee et al.,J. Molec. Catalysis 26:119-129 (2003)); Degenerate Oligonucleotide GeneShuffling (DOGS), in which degenerate primers are used to controlrecombination between molecules; (Bergquist and Gibbs, Methods Mol.Biol. 352:191-204 (2007); Bergquist et al., Biomol. Eng 22:63-72 (2005);Gibbs et al., Gene 271:13-20 (2001)); Incremental Truncation for theCreation of Hybrid Enzymes (ITCHY), which creates a combinatoriallibrary with 1 base pair deletions of a gene or gene fragment ofinterest (Ostermeier et al., Proc. Natl. Acad. Sci. USA 96:3562-3567(1999); and Ostermeier et al., Nat. Biotechnol. 17:1205-1209 (1999));Thio-Incremental Truncation for the Creation of Hybrid Enzymes(THIO-ITCHY), which is similar to ITCHY except that phosphothioate dNTPsare used to generate truncations (Lutz et al., Nucleic Acids Res 29:E16(2001)); SCRATCHY, which combines two methods for recombining genes,ITCHY and DNA shuffling (Lutz et al., Proc. Natl. Acad. Sci. USA98:11248-11253 (2001)); Random Drift Mutagenesis (RNDM), in whichmutations made via epPCR are followed by screening/selection for thoseretaining usable activity (Bergquist et al., Biomol. Eng. 22:63-72(2005)); Sequence Saturation Mutagenesis (SeSaM), a random mutagenesismethod that generates a pool of random length fragments using randomincorporation of a phosphothioate nucleotide and cleavage, which is usedas a template to extend in the presence of “universal” bases such asinosine, and replication of an inosine-containing complement givesrandom base incorporation and, consequently, mutagenesis (Wong et al.,Biotechnol. J. 3:74-82 (2008); Wong et al., Nucleic Acids Res. 32:e26(2004); and Wong et al., Anal. Biochem. 341:187-189 (2005)); SyntheticShuffling, which uses overlapping oligonucleotides designed to encode“all genetic diversity in targets” and allows a very high diversity forthe shuffled progeny (Ness et al., Nat. Biotechnol. 20:1251-1255(2002)); Nucleotide Exchange and Excision Technology NexT, whichexploits a combination of dUTP incorporation followed by treatment withuracil DNA glycosylase and then piperidine to perform endpoint DNAfragmentation (Muller et al., Nucleic Acids Res. 33:e117 (2005)).

Further methods include Sequence Homology-Independent ProteinRecombination (SHIPREC), in which a linker is used to facilitate fusionbetween two distantly related or unrelated genes, and a range ofchimeras is generated between the two genes, resulting in libraries ofsingle-crossover hybrids (Sieber et al., Nat. Biotechnol. 19:456-460(2001)); Gene Site Saturation Mutagenesis™ (GSSM™), in which thestarting materials include a supercoiled double stranded DNA (dsDNA)plasmid containing an insert and two primers which are degenerate at thedesired site of mutations (Kretz et al., Methods Enzymol. 388:3-11(2004)); Combinatorial Cassette Mutagenesis (CCM), which involves theuse of short oligonucleotide cassettes to replace limited regions with alarge number of possible amino acid sequence alterations (Reidhaar-Olsonet al. Methods Enzymol. 208:564-586 (1991); and Reidhaar-Olson et al.Science 241:53-57 (1988)); Combinatorial Multiple Cassette Mutagenesis(CMCM), which is essentially similar to CCM and uses epPCR at highmutation rate to identify hot spots and hot regions and then extensionby CMCM to cover a defined region of protein sequence space (Reetz etal., Angew. Chem. Int. Ed Engl. 40:3589-3591 (2001)); the MutatorStrains technique, in which conditional is mutator plasmids, utilizingthe mutD5 gene, which encodes a mutant subunit of DNA polymerase III, toallow increases of 20 to 4000-X in random and natural mutation frequencyduring selection and block accumulation of deleterious mutations whenselection is not required (Selifonova et al., Appl. Environ. Microbiol.67:3645-3649 (2001)); Low et al., J. Mol. Biol. 260:359-3680 (1996)).

Additional exemplary methods include Look-Through Mutagenesis (LTM),which is a multidimensional mutagenesis method that assesses andoptimizes combinatorial mutations of selected amino acids (Rajpal etal., Proc. Natl. Acad. Sci. USA 102:8466-8471 (2005)); Gene Reassembly,which is a DNA shuffling method that can be applied to multiple genes atone time or to create a large library of chimeras (multiple mutations)of a single gene (Tunable GeneReassembly™ (TGR™) Technology supplied byVerenium Corporation), in Silico Protein Design Automation (PDA), whichis an optimization algorithm that anchors the structurally definedprotein backbone possessing a particular fold, and searches sequencespace for amino acid substitutions that can stabilize the fold andoverall protein energetics, and generally works most effectively onproteins with known three-dimensional structures (Hayes et al., Proc.Natl. Acad. Sci. USA 99:15926-15931 (2002)); and Iterative SaturationMutagenesis (ISM), which involves using knowledge of structure/functionto choose a likely site for enzyme improvement, performing saturationmutagenesis at chosen site using a mutagenesis method such as StratageneQuikChange (Stratagene; San Diego Calif.), screening/selecting fordesired properties, and, using improved clone(s), starting over atanother site and continue repeating until a desired activity is achieved(Reetz et al., Nat. Protoc. 2:891-903 (2007); and Reetz et al., Angew.Chem. Int. Ed Engl. 45:7745-7751 (2006)).

Any of the aforementioned methods for mutagenesis can be used alone orin any combination. Additionally, any one or combination of the directedevolution methods can be used in conjunction with adaptive evolutiontechniques, as described herein.

It is understood that modifications which do not substantially affectthe activity of the various embodiments of this invention are alsoprovided within the definition of the invention provided herein.Accordingly, the following examples are intended to illustrate but notlimit the present invention.

EXAMPLE I Enzyme Candidates for Catalyzing Steps A-E of FIG. 1

Alcohol Kinase (FIG. 1, Step A)

Alcohol kinase enzymes catalyze the transfer of a phosphate group to ahydroxyl group. Kinases that catalyze transfer of a phosphate group toan alcohol group are members of the EC 2.7.1 enzyme class. The tablebelow lists several useful kinase enzymes in the EC 2.7.1 enzyme class.

Enzyme Commission Number Enzyme Name 2.7.1.1 hexokinase 2.7.1.2glucokinase 2.7.1.3 ketohexokinase 2.7.1.4 fructokinase 2.7.1.5rhamnulokinase 2.7.1.6 galactokinase 2.7.1.7 mannokinase 2.7.1.8glucosamine kinase 2.7.1.10 phosphoglucokinase 2.7.1.116-phosphofructokinase 2.7.1.12 gluconokinase 2.7.1.13dehydrogluconokinase 2.7.1.14 sedoheptulokinase 2.7.1.15 ribokinase2.7.1.16 ribulokinase 2.7.1.17 xylulokinase 2.7.1.18 phosphoribokinase2.7.1.19 phosphoribulokinase 2.7.1.20 adenosine kinase 2.7.1.21thymidine kinase 2.7.1.22 ribosylnicotinamide kinase 2.7.1.23 NAD+kinase 2.7.1.24 dephospho-CoA kinase 2.7.1.25 adenylyl-sulfate kinase2.7.1.26 riboflavin kinase 2.7.1.27 erythritol kinase 2.7.1.28triokinase 2.7.1.29 glycerone kinase 2.7.1.30 glycerol kinase 2.7.1.31glycerate kinase 2.7.1.32 choline kinase 2.7.1.33 pantothenate kinase2.7.1.34 pantetheine kinase 2.7.1.35 pyridoxal kinase 2.7.1.36mevalonate kinase 2.7.1.39 homoserine kinase 2.7.1.40 pyruvate kinase2.7.1.41 glucose-1-phosphate phosphodismutase 2.7.1.42 riboflavinphosphotransferase 2.7.1.43 glucuronokinase 2.7.1.44 galacturonokinase2.7.1.45 2-dehydro-3- deoxygluconokinase 2.7.1.46 L-arabinokinase2.7.1.47 D-ribulokinase 2.7.1.48 uridine kinase 2.7.1.49hydroxymethylpyrimidine kinase 2.7.1.50 hydroxyethylthiazole kinase2.7.1.51 L-fuculokinase 2.7.1.52 fucokinase 2.7.1.53 L-xylulokinase2.7.1.54 D-arabinokinase 2.7.1.55 allose kinase 2.7.1.561-phosphofructokinase 2.7.1.58 2-dehydro-3- deoxygalactonokinase2.7.1.59 N-acetylglucosamine kinase 2.7.1.60 N-acylmannosamine kinase2.7.1.61 acyl-phosphate-hexose phosphotransferase 2.7.1.62phosphoramidate-hexose phosphotransferase 2.7.1.63 polyphosphate-glucosephosphotransferase 2.7.1.64 inositol 3-kinase 2.7.1.65 scyllo-inosamine4-kinase 2.7.1.66 undecaprenol kinase 2.7.1.67 1-phosphatidylinositol 4-kinase 2.7.1.68 1-phosphatidylinositol-4- phosphate 5-kinase 2.7.1.69protein-Np- phosphohistidine-sugar phosphotransferase 2.7.1.70 identicalto EC 2.7.1.37. 2.7.1.71 shikimate kinase 2.7.1.72 streptomycin 6-kinase2.7.1.73 inosine kinase 2.7.1.74 deoxycytidine kinase 2.7.1.76deoxyadenosine kinase 2.7.1.77 nucleoside phosphotransferase 2.7.1.78polynucleotide 5′-hydroxyl- kinase 2.7.1.79 diphosphate-glycerolphosphotransferase 2.7.1.80 diphosphate-serine phosphotransferase2.7.1.81 hydroxylysine kinase 2.7.1.82 ethanolamine kinase 2.7.1.83pseudouridine kinase 2.7.1.84 alkylglycerone kinase 2.7.1.85 β-glucosidekinase 2.7.1.86 NADH kinase 2.7.1.87 streptomycin 3″-kinase 2.7.1.88dihydrostreptomycin-6- phosphate 3′a-kinase 2.7.1.89 thiamine kinase2.7.1.90 diphosphate-fructose-6- phosphate 1- phosphotransferase2.7.1.91 sphinganine kinase 2.7.1.92 5-dehydro-2- deoxygluconokinase2.7.1.93 alkylglycerol kinase 2.7.1.94 acylglycerol kinase 2.7.1.95kanamycin kinase 2.7.1.100 S-methyl-5-thioribose kinase 2.7.1.101tagatose kinase 2.7.1.102 hamamelose kinase 2.7.1.103 viomycin kinase2.7.1.105 6-phosphofructo-2-kinase 2.7.1.106 glucose-1,6-bisphosphatesynthase 2.7.1.107 diacylglycerol kinase 2.7.1.108 dolichol kinase2.7.1.113 deoxyguanosine kinase 2.7.1.114 AMP-thymidine kinase 2.7.1.118ADP-thymidine kinase 2.7.1.119 hygromycin-B 7″-O-kinase 2.7.1.121phosphoenolpyruvate- glycerone phosphotransferase 2.7.1.122 xylitolkinase 2.7.1.127 inositol-trisphosphate 3- kinase 2.7.1.130tetraacyldisaccharide 4′- kinase 2.7.1.134 inositol-tetrakisphosphate1-kinase 2.7.1.136 macrolide 2′-kinase 2.7.1.137 phosphatidylinositol 3-kinase 2.7.1.138 ceramide kinase 2.7.1.140 inositol-tetrakisphosphate5-kinase 2.7.1.142 glycerol-3-phosphate- glucose phosphotransferase2.7.1.143 diphosphate-purine nucleoside kinase 2.7.1.144tagatose-6-phosphate kinase 2.7.1.145 deoxynucleoside kinase 2.7.1.146ADP-dependent phosphofructokinase 2.7.1.147 ADP-dependent glucokinase2.7.1.148 4-(cytidine 5′-diphospho)- 2-C-methyl-D-erythritol kinase2.7.1.149 1-phosphatidylinositol-5- phosphate 4-kinase 2.7.1.1501-phosphatidylinositol-3- phosphate 5-kinase 2.7.1.151inositol-polyphosphate multikinase 2.7.1.153 phosphatidylinositol-4,5-bisphosphate 3-kinase 2.7.1.154 phosphatidylinositol-4- phosphate3-kinase 2.7.1.156 adenosylcobinamide kinase 2.7.1.157N-acetylgalactosamine kinase 2.7.1.158 inositol-pentakisphosphate2-kinase 2.7.1.159 inositol-1,3,4-trisphosphate 5/6-kinase 2.7.1.1602′-phosphotransferase 2.7.1.161 CTP-dependent riboflavin kinase2.7.1.162 N-acetylhexosamine 1- kinase 2.7.1.163 hygromycin B 4-O-kinase2.7.1.164 O-phosphoseryl-tRNASec kinase

Mevalonate kinase (EC 2.7.1.36) phosphorylates the terminal hydroxylgroup of mevalonate. Gene candidates for this step include erg12 from S.cerevisiae, mvk from Methanocaldococcus jannaschi, MVK from Homosapeins, and mvk from Arabidopsis thaliana col. Additional mevalonatekinase candidates include the feedback-resistant mevalonate kinase fromthe archeon Methanosarcina mazei (Primak et al, AEM, in press (2011))and the Mvk protein from Streptococcus pneumoniae (Andreassi et al,Protein Sci, 16:983-9 (2007)). Mvk proteins from S. cerevisiae, S.pneumoniae and M. mazei were heterologously expressed and characterizedin E. coli (Primak et al, supra). The S. pneumoniae mevalonate kinasewas active on several alternate substrates includingcylopropylmevalonate, vinylmevalonate and ethynylmevalonate (Kudoh etal, Bioorg Med Chem 18:1124-34 (2010)), and a subsequent studydetermined that the ligand binding site is selective for compact,electron-rich C(3)-substituents (Lefurgy et al, J Biol Chem 285:20654-63(2010)).

Protein GenBank ID GI Number Organism erg12 CAA39359.1 3684Sachharomyces cerevisiae mvk Q58487.1 2497517 Methanocaldococcusjannaschii mvk AAH16140.1 16359371 Homo sapiens mvk NP_851084.1 30690651Arabidopsis thaliana mvk NP_633786.1 21227864 Methanosarcina mazei mvkNP_357932.1 15902382 Streptococcus pneumoniae

Glycerol kinase also phosphorylates the terminal hydroxyl group inglycerol to form glycerol-3-phosphate. This reaction occurs in severalspecies, including Escherichia coli, Saccharomyces cerevisiae, andThermotoga maritima. The E. coli glycerol kinase has been shown toaccept alternate substrates such as dihydroxyacetone and glyceraldehyde(Hayashi et al., J. Biol. Chem. 242:1030-1035 (1967)). T. maritime hastwo glycerol kinases (Nelson et al., Nature 399:323-329 (1999)).Glycerol kinases have been shown to have a wide range of substratespecificity. Crans and Whiteside studied glycerol kinases from fourdifferent organisms (Escherichia coli, S. cerevisiae, Bacillusstearothermophilus, and Candida mycoderma) (Crans et al., J. Am. Chem.Soc. 107:7008-7018 (2010); Nelson et al., supra, (1999)). They studied66 different analogs of glycerol and concluded that the enzyme couldaccept a range of substituents in place of one terminal hydroxyl groupand that the hydrogen atom at C2 could be replaced by a methyl group.Interestingly, the kinetic constants of the enzyme from all fourorganisms were very similar.

Protein GenBank ID GI Number Organism glpK AP_003883.1 89110103Escherichia coli K12 glpK1 NP_228760.1 15642775 Thermotoga maritime MSB8glpK2 NP_229230.1 15642775 Thermotoga maritime MSB8 Gut1 NP_011831.182795252 Saccharomyces cerevisiae

Homoserine kinase is another possible candidate. This enzyme is alsopresent in a number of organisms including E. coli, Streptomyces sp, andS. cerevisiae. Homoserine kinase from E. coli has been shown to haveactivity on numerous substrates, including, L-2-amino,1,4-butanediol,aspartate semialdehyde, and 2-amino-5-hydroxyvalerate (Huo et al.,Biochemistry 35:16180-16185 (1996); Huo et al., Arch. Biochem. Biophys.330:373-379 (1996)). This enzyme can act on substrates where thecarboxyl group at the alpha position has been replaced by an ester or bya hydroxymethyl group. The gene candidates are:

Protein GenBank ID GI Number Organism thrB BAB96580.2 85674277Escherichia coli K12 SACT1DRAFT_4809 ZP_06280784.1 282871792Streptomyces sp. ACT-1 Thr1 AAA35154.1 172978 Saccharomyces serevisiaePhosphate Lyase (FIG. 1, Step B)

Phosphate lyase enzymes catalyze the conversion of alkyl phosphates toalkenes. Carbon-oxygen lyases that operate on phosphates are found inthe EC 4.2.3 enzyme class. The table below lists several relevantenzymes in EC class 4.2.3.

Enzyme Commission Number Enzyme Name 4.2.3.5 Chorismate synthase4.2.3.15 Myrcene synthase 4.2.3.26 Linalool synthase 4.2.3.27 Isoprenesynthase 4.2.3.36 Terpentriene sythase 4.2.3.46 (E,E)-alpha-Farnesenesynthase 4.2.3.47 Beta-Farnesene synthase 4.2.3.49 Nerolidol synthase

Chorismate synthase (EC 4.2.3.5) participates in the shikimate pathway,catalyzing the dephosphorylation of 5-enolpyruvylshikimate-3-phosphateto chorismate. The enzyme requires reduced flavin mononucleotide (FMN)as a cofactor, although the net reaction of the enzyme does not involvea redox change. In contrast to the enzyme found in plants and bacteria,the chorismate synthase in fungi is also able to reduce FMN at theexpense of NADPH (Macheroux et al., Planta 207:325-334 (1999)).Representative monofunctional enzymes are encoded by aroC of E. coli(White et al., Biochem. J. 251:313-322 (1988)) and Streptococcuspneumoniae (Maclean and Ali, Structure 11:1499-1511 (2003)).Bifunctional fungal enzymes are found in Neurospora crassa (Kitzing etal., J. Biol. Chem. 276:42658-42666 (2001)) and Saccharomyces cerevisiae(Jones et al., Mol. Microbiol. 5:2143-2152 (1991)).

GenBank Accession Gene No. GI No. Organism aroC NP_416832.1 16130264Escherichia coli aroC ACH47980.1 197205483 Streptococcus pneumoniaeU25818.1:19..1317 AAC49056.1 976375 Neurospora crassa ARO2 CAA42745.13387 Saccharomyces cerevisiae

Isoprene synthase naturally catalyzes the conversion of dimethylallyldiphosphate to isoprene, but can also catalyze the synthesis of1,3-butadiene from 2-butenyl-4-diphosphate. Isoprene synthases can befound in several organisms including Populus alba (Sasaki et al., FEBSLetters, 2005, 579 (11), 2514-2518), Pueraria montana (Lindberg et al.,Metabolic Eng, 12(1):70-79 (2010); Sharkey et al., Plant Physiol.,137(2):700-712 (2005)), and Populus tremula×Populus alba, also calledPopulus canescens (Miller et al., Planta, 2001, 213 (3), 483-487). Thecrystal structure of the Populus canescens isoprene synthase wasdetermined (Koksal et al, J Mol Biol 402:363-373 (2010)). Additionalisoprene synthase enzymes are described in (Chotani et al.,WO/2010/031079, Systems Using Cell Culture for Production of Isoprene;Cervin et al., US Patent Application 20100003716, Isoprene SynthaseVariants for Improved Microbial Production of Isoprene).

Protein GenBank ID GI Number Organism ispS BAD98243.1 63108310 Populusalba ispS AAQ84170.1 35187004 Pueraria montana ispS CAC35696.1 13539551Populus tremula x Populus alba

Myrcene synthase enzymes catalyze the dephosphorylation of geranyldiphosphate to beta-myrcene (EC 4.2.3.15). Exemplary myrcene synthasesare encoded by MST2 of Solanum lycopersicum (van Schie et al, Plant MolBiol 64:D473-79 (2007)), TPS-Myr of Picea abies (Martin et al, PlantPhysiol 135:1908-27 (2004)) g-myr of Abies grandis (Bohlmann et al, JBiol Chem 272:21784-92 (1997)) and TPS10 of Arabidopsis thaliana(Bohlmann et al, Arch Biochem Biophys 375:261-9 (2000)). These enzymeswere heterologously expressed in E. coli.

Protein GenBank ID GI Number Organism MST2 ACN58229.1 224579303 Solanumlycopersicum TPS-Myr AAS47690.2 77546864 Picea abies G-myr O24474.117367921 Abies grandis TPS10 EC07543.1 330252449 Arabidopsis thaliana

Farnesyl diphosphate is converted to alpha-farnesene and beta-farneseneby alpha-farnesene synthase and beta-farnesene synthase, respectively.Exemplary alpha-farnesene synthase enzymes include TPS03 and TPS02 ofArabidopsis thaliana (Faldt et al, Planta 216:745-51 (2003); Huang etal, Plant Physiol 153:1293-310 (2010)), afs of Cucumis sativus (Merckeet al, Plant Physiol 135:2012-14 (2004), eafar of Malus×domestica (Greenet al, Phytochem 68:176-88 (2007)) and TPS-Far of Picea abies (Martin,supra). An exemplary beta-farnesene synthase enzyme is encoded by TPS1of Zea mays (Schnee et al, Plant Physiol 130:2049-60 (2002)).

Protein GenBank ID GI Number Organism TPS03 A4FVP2.1 205829248Arabidopsis thaliana TPS02 P0CJ43.1 317411866 Arabidopsis thalianaTPS-Far AAS47697.1 44804601 Picea abies afs AAU05951.1 51537953 Cucumissativus eafar Q84LB2.2 75241161 Malus x domestica TPS1 Q84ZW8.1 75149279Zea maysDiphosphokinase (FIG. 1, Step C)

Diphosphokinase enzymes catalyze the transfer of a diphosphate group toan alcohol group. The enzymes described below naturally possess suchactivity. Kinases that catalyze transfer of a diphosphate group aremembers of the EC 2.7.6 enzyme class. The table below lists severaluseful kinase enzymes in the EC 2.7.6 enzyme class.

Enzyme Commission No. Enzyme Name 2.7.6.1 ribose-phosphatediphosphokinase 2.7.6.2 thiamine diphosphokinase 2.7.6.32-amino-4-hydroxy-6- hydroxymethyldihydropteridine diphosphokinase2.7.6.4 nucleotide diphosphokinase 2.7.6.5 GTP diphosphokinase

Of particular interest are ribose-phosphate diphosphokinase enzymes,which have been identified in Escherichia coli (Hove-Jenson et al., JBiol Chem, 1986, 261(15); 6765-71) and Mycoplasma pneumoniae M129(McElwain et al, International Journal of Systematic Bacteriology, 1988,38:417-423) as well as thiamine diphosphokinase enzymes. Exemplarythiamine diphosphokinase enzymes are found in Arabidopsis thaliana(Ajjawi, Plant Mol Biol, 2007, 65(1-2); 151-62).

Protein GenBank ID GI Number Organism prs NP_415725.1 16129170Escherichia coli prsA NP_109761.1 13507812 Mycoplasma pneumoniae M129TPK1 BAH19964.1 222424006 Arabidopsis thaliana col TPK2 BAH57065.1227204427 Arabidopsis thaliana colAlkyl Phosphate Kinase (FIG. 1, Step D)

Alkyl phosphate kinase enzymes catalyze the transfer of a phosphategroup to the phosphate group of an alkyl phosphate. The enzymesdescribed below naturally possess such activity or can be engineered toexhibit this activity. Kinases that catalyze transfer of a phosphategroup to another phosphate group are members of the EC 2.7.4 enzymeclass. The table below lists several useful kinase enzymes in the EC2.7.4 enzyme class.

Enzyme Commission No. Enzyme Name 2.7.4.1 polyphosphate kinase 2.7.4.2phosphomevalonate kinase 2.7.4.3 adenylate kinase 2.7.4.4nucleoside-phosphate kinase 2.7.4.6 nucleoside-diphosphate kinase2.7.4.7 phosphomethylpyrimidine kinase 2.7.4.8 guanylate kinase 2.7.4.9dTMP kinase 2.7.4.10 nucleoside-triphosphate-adenylate kinase 2.7.4.11(deoxy)adenylate kinase 2.7.4.12 T2-induced deoxynucleotide kinase2.7.4.13 (deoxy)nucleoside-phosphate kinase 2.7.4.14 cytidylate kinase2.7.4.15 thiamine-diphosphate kinase 2.7.4.16 thiamine-phosphate kinase2.7.4.17 3-phosphoglyceroyl-phosphate-polyphosphate phosphotransferase2.7.4.18 farnesyl-diphosphate kinase 2.7.4.195-methyldeoxycytidine-5′-phosphate kinase 2.7.4.20dolichyl-diphosphate-polyphosphate phosphotransferase 2.7.4.21inositol-hexakisphosphate kinase 2.7.4.22 UMP kinase 2.7.4.23 ribose1,5-bisphosphate phosphokinase 2.7.4.24diphosphoinositol-pentakisphosphate kinase 2.7.4.— Farnesylmonophosphate kinase 2.7.4.— Geranyl-geranyl monophosphate kinase2.7.4.— Phytyl-phosphate kinase

Phosphomevalonate kinase enzymes are of particular interest.Phosphomevalonate kinase (EC 2.7.4.2) catalyzes the phosphorylation ofphosphomevalonate. This enzyme is encoded by erg8 in Saccharomycescerevisiae (Tsay et al., Mol. Cell Biol. 11:620-631 (1991)) and mvaK2 inStreptococcus pneumoniae, Staphylococcus aureus and Enterococcusfaecalis (Doun et al., Protein Sci. 14:1134-1139 (2005); Wilding et al.,J. Bacteriol. 182:4319-4327 (2000)). The Streptococcus pneumoniae andEnterococcus faecalis enzymes were cloned and characterized in E. coli(Pilloff et al., J. Biol. Chem. 278:4510-4515 (2003); Doun et al.,Protein Sci. 14:1134-1139 (2005)). The S. pneumoniae phosphomevalonatekinase was active on several alternate substrates includingcylopropylmevalonate phosphate, vinylmevalonate phosphate andethynylmevalonate phosphate (Kudoh et al, Bioorg Med Chem 18:1124-34(2010)).

Protein GenBank ID GI Number Organism Erg8 AAA34596.1 171479Saccharomyces cerevisiae mvaK2 AAG02426.1 9937366 Staphylococcus aureusmvaK2 AAG02457.1 9937409 Streptococcus pneumoniae mvaK2 AAG02442.19937388 Enterococcus faecalis

Farnesyl monophosphate kinase enzymes catalyze the CTP dependentphosphorylation of farnesyl monophosphate to farnesyl diphosphate.Similarly, geranylgeranyl phosphate kinase catalyzes CTP dependentphosphorylation. Enzymes with these activities were identified in themicrosomal fraction of cultured Nicotiana tabacum (That et al, PNAS96:13080-5 (1999)). However, the associated genes have not beenidentified to date.

Diphosphate Lyase (FIG. 1, Step E)

Diphosphate lyase enzymes catalyze the conversion of alkyl diphosphatesto alkenes. Carbon-oxygen lyases that operate on phosphates are found inthe EC 4.2.3 enzyme class. The table below lists several useful enzymesin EC class 4.2.3. Exemplary enzyme candidates were described above (seephosphate lyase section).

Enzyme Commission No. Enzyme Name 4.2.3.5 Chorismate synthase 4.2.3.15Myrcene synthase 4.2.3.27 Isoprene synthase 4.2.3.36 Terpentrienesythase 4.2.3.46 (E,E)-alpha-Farnesene synthase 4.2.3.47 Beta-Farnesenesynthase

EXAMPLE II Preparation of an Isobutylene Producing Microbial Organism

This example describes the generation of a microbial organism capable ofproducing isobutylene from isobutanol, in an organism engineered to havean isobutylene pathway.

An isobutanol-overproducing strain of Escherichia coli is used as atarget organism to engineer an isobutylene-producing pathway. Pathwaysfor efficiently converting central metabolic intermediates to isobutanolare known in the art (for example: U.S. Pat. No. 8,017,375;PCT/US2006/041602; PCT/US2008/053514; PCT/US2006/041602; Dickinson etal., JBC 273:25751-56 (1998)) and isobutanol overproducing E. colistrains have been developed (for example, Atsumi et al, Appl MicrobiolBiotech 85:651-57 (2010)).

To generate an E. coli strain engineered to produce isobutylene fromisobutanol, nucleic acids encoding the enzymes utilized in the pathwayof FIG. 1 are expressed in E. coli using well known molecular biologytechniques (see, for example, Sambrook, supra, 2001; Ausubel supra,1999; Roberts et al., supra, 1989). In particular, the mvk(NP_357932.1), mvaK2 (AAG02457.1) and, ispS (CAC35696.1) genes encodingalkyl phosphate kinase, alkyl diphosphate kinase and isobutylenesynthetase, respectively, are cloned into the pZE13 vector (Expressys,Ruelzheim, Germany), under the control of the PA1/lacO promoter. Thisplasmid is then transformed into a host strain containing lacI^(Q),which allows inducible expression by addition ofisopropyl-beta-D-1-thiogalactopyranoside (IPTG).

The resulting genetically engineered organism is cultured in glucosecontaining medium following procedures well known in the art (see, forexample, Sambrook et al., supra, 2001). The expression of isobutylenepathway genes is corroborated using methods well known in the art fordetermining polypeptide expression or enzymatic activity, including forexample, Northern blots, PCR amplification of mRNA and immunoblotting.Enzymatic activities of the expressed enzymes are confirmed using assaysspecific for the individually activities. The ability of the engineeredE. coli strain to produce isobutylene is confirmed using HPLC, gaschromatography-mass spectrometry (GCMS) or liquid chromatography-massspectrometry (LCMS).

Microbial strains engineered to have a functional isobutylene synthesispathway are further augmented by optimization for efficient utilizationof the pathway. Briefly, the engineered strain is assessed to determinewhether any of the exogenous genes are expressed at a rate limitinglevel. Expression is increased for any enzymes expressed at low levelsthat can limit the flux through the pathway by, for example,introduction of additional gene copy numbers. Strategies are alsoapplied to improve production of isobutylene precursorisobutanoyl-phosphate, such as mutagenesis, cloning and/or deletion ofnative genes involved in byproduct formation.

To generate better producers, metabolic modeling is utilized to optimizegrowth conditions. Modeling is also used to design gene knockouts thatadditionally optimize utilization of the pathway (see, for example, U.S.patent publications US 2002/0012939, US 2003/0224363, US 2004/0029149,US 2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466,and in U.S. Pat. No. 7,127,379). Modeling analysis allows reliablepredictions of the effects on cell growth of shifting the metabolismtowards more efficient production of isobutylene. One modeling method isthe bilevel optimization approach, OptKnock (Burgard et al., Biotechnol.Bioengineer. 84:647-657 (2003)), which is applied to select geneknockouts that collectively result in better production of isobutylene.Adaptive evolution also can be used to generate better producers of, forexample, the isobutanoyl-phosphate intermediate or the isobutyleneproduct. Adaptive evolution is performed to improve both growth andproduction characteristics (Fong and Palsson, Nat. Genet. 36:1056-1058(2004); Alper et al., Science 314:1565-1568 (2006)). Based on theresults, subsequent rounds of modeling, genetic engineering and adaptiveevolution can be applied to the isobutylene producer to further increaseproduction.

For large-scale production of isobutylene, the above isobutylenepathway-containing organism is cultured in a fermenter using a mediumknown in the art to support growth of the organism under anaerobicconditions. Fermentations are performed in either a batch, fed-batch orcontinuous manner. Anaerobic conditions are maintained by first spargingthe medium with nitrogen and then sealing culture vessel (e.g., flaskscan be sealed with a septum and crimp-cap). Microaerobic conditions alsocan be utilized by providing a small hole for limited aeration. The pHof the medium is maintained at a pH of 7 by addition of an acid, such asH2SO4. The growth rate is determined by measuring optical density usinga spectrophotometer (600 nm), and the glucose uptake rate by monitoringcarbon source depletion over time. Byproducts such as undesirablealcohols, organic acids, and residual glucose can be quantified by HPLC(Shimadzu) with an HPX-087 column (BioRad), using a refractive indexdetector for glucose and alcohols, and a UV detector for organic acids,Lin et al., Biotechnol. Bioeng., 775-779 (2005).

EXAMPLE III Pathways for the Formation of Butadiene Precursor3-Buten-1-Ol (but-3-En-1-Ol) from Pyruvate and Acetaldehyde

This example describes pathways for converting pyruvate and acetaldehydeto 3-buten-1-ol, and further to butadiene. The conversion of pyruvateand acetaldehyde to 3-buten-1-ol is accomplished in four enzymaticsteps. Pyruvate and acetaldehyde are first condensed to4-hydroxy-2-oxovalerate by 4-hydroxy-2-ketovalerate aldolase. The4-hydroxy-2-oxovalerate product is subsequently dehydrated to2-oxopentenoate. Decarboxylation of 2-oxopentenoate yields 3-buten-1-al,which is further reduced to 3-buten-1-ol by an alcohol dehydrogenase.

Enzymes and gene candidates for catalyzing but-3-en-1-ol pathwayreactions are described in further detail below.

The condensation of pyruvate and acetaldehyde to 4-hydroxy-2-oxovalerateis catalyzed by 4-hydroxy-2-oxovalerate aldolase (EC 4.1.3.39). Thisenzyme participates in pathways for the degradation of phenols, cresolsand catechols. The E. coli enzyme, encoded by mhpE, is highly specificfor acetaldehyde as an acceptor but accepts the alternate substrates2-ketobutyrate or phenylpyruvate as donors (Pollard et al., Appl EnvironMicrobiol 64:4093-4094 (1998)). Similar enzymes are encoded by the cmtGand todH genes of Pseudomonas putida (Lau et al., Gene 146:7-13 (1994);Eaton, J. Bacteriol. 178:1351-1362 (1996)). In Pseudomonas CF600, thisenzyme is part of a bifunctional aldolase-dehydrogenase heterodimerencoded by dmpFG (Manjasetty et al., Acta Crystallogr. D. BiolCrystallogr. 57:582-585 (2001)). The dehydrogenase functionalityinterconverts acetaldehyde and acetyl-CoA, providing the advantage ofreduced cellular concentrations of acetaldehyde, toxic to some cells.

Gene GenBank ID GI Number Organism mhpE AAC73455.1 1786548 Escherichiacoli cmtG AAB62295.1 1263190 Pseudomonas putida todH AAA61944.1 485740Pseudomonas putida dmpG CAA43227.1 45684 Pseudomonas sp. CF600 dmpFCAA43226.1 45683 Pseudomonas sp. CF600

Dehydration of 4-hydroxy-2-oxovalerate to 2-oxopentenoate is catalyzedby 4-hydroxy-2-oxovalerate hydratase (EC 4.2.1.80). This enzymeparticipates in aromatic degradation pathways and is typicallyco-transcribed with a gene encoding an enzyme with4-hydroxy-2-oxovalerate aldolase activity. Exemplary gene products areencoded by mhpD of E. coli (Ferrandez et al., J. Bacteriol.179:2573-2581 (1997); Pollard et al., Eur J. Biochem. 251:98-106(1998)), todG and cmtF of Pseudomonas putida (Lau et al., Gene 146:7-13(1994); Eaton, J. Bacteriol. 178:1351-1362 (1996)), cnbE of Comamonassp. CNB-1 (Ma et al., Appl Environ Microbiol 73:4477-4483 (2007)) andmhpD of Burkholderia xenovorans (Wang et al., FEBS J 272:966-974(2005)). A closely related enzyme, 2-oxohepta-4-ene-1,7-dioatehydratase, participates in 4-hydroxyphenylacetic acid degradation, whereit converts 2-oxo-hept-4-ene-1,7-dioate (OHED) to2-oxo-4-hydroxy-hepta-1,7-dioate using magnesium as a cofactor (Burks etal., J. Am. Chem. Soc. 120: (1998)). OHED hydratase enzyme candidateshave been identified and characterized in E. coli C (Roper et al., Gene156:47-51 (1995); Izumi et al., J. Mol. Biol. 370:899-911 (2007)) and E.coli W (Prieto et al., J. Bacteriol. 178:111-120 (1996)). Sequencecomparison reveals homologs in a wide range of bacteria, plants andanimals. Enzymes with highly similar sequences are contained inKlebsiella pneumonia (91% identity, eval=2e-138) and Salmonella enterica(91% identity, eval=4e-138), among others.

GenBank Protein Accession No. GI No. Organism mhpD AAC73453.2 87081722Escherichia coli cmtF AAB62293.1 1263188 Pseudomonas putida todGAAA61942.1 485738 Pseudomonas putida cnbE YP_001967714.1 190572008Comamonas sp. CNB-1 mhpD Q13VU0 123358582 Burkholderia xenovorans hpcGCAA57202.1 556840 Escherichia coli C hpaH CAA86044.1 757830 Escherichiacoli W hpaH ABR80130.1 150958100 Klebsiella pneumoniae Sari_01896ABX21779.1 160865156 Salmonella enterica

Decarboxylation of 4-hydroxy-2-oxovalerate is catalyzed by a keto-aciddecarboxylase. Suitable enzyme candidates include pyruvate decarboxylase(EC 4.1.1.1), benzoylformate decarboxylase (EC 4.1.1.7),alpha-ketoglutarate decarboxylase and branched-chain alpha-ketoaciddecarboxylase. Pyruvate decarboxylase (PDC), also termed keto-aciddecarboxylase, is a key enzyme in alcoholic fermentation, catalyzing thedecarboxylation of pyruvate to acetaldehyde. The enzyme fromSaccharomyces cerevisiae has a broad substrate range for aliphatic2-keto acids including 2-ketobutyrate, 2-ketovalerate, 3-hydroxypyruvateand 2-phenylpyruvate (22). This enzyme has been extensively studied,engineered for altered activity, and functionally expressed in E. coli(Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001); Li etal., Biochemistry. 38:10004-10012 (1999); ter Schure et al., Appl.Environ. Microbiol. 64:1303-1307 (1998)). The PDC from Zymomonasmobilus, encoded by pdc, also has a broad substrate range and has been asubject of directed engineering studies to alter the affinity fordifferent substrates (Siegert et al., Protein Eng Des Sel 18:345-357(2005)). The crystal structure of this enzyme is available(Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001)). Otherwell-characterized PDC candidates include the enzymes from Acetobacterpasteurians (Chandra et al., 176:443-451 (2001)) and Kluyveromyceslactis (Krieger et al., 269:3256-3263 (2002)).

Protein GenBank ID GI Number Organism pdc P06672.1 118391 Zymomonasmobilis pdc1 P06169 30923172 Saccharomyces cerevisiae pdc Q8L38820385191 Acetobacter pasteurians pdc1 Q12629 52788279 Kluyveromyceslactis

Like PDC, benzoylformate decarboxylase (EC 4.1.1.7) has a broadsubstrate range and has been the target of enzyme engineering studies.The enzyme from Pseudomonas putida has been extensively studied andcrystal structures of this enzyme are available (Polovnikova et al.,42:1820-1830 (2003); Hasson et al., 37:9918-9930 (1998)). Site-directedmutagenesis of two residues in the active site of the Pseudomonas putidaenzyme altered the affinity (Km) of naturally and non-naturallyoccurring substrates (Siegert et al., Protein Eng Des Sel 18:345-357(2005)). The properties of this enzyme have been further modified bydirected engineering (Lingen et al., Chembiochem. 4:721-726 (2003);Lingen et al., Protein Eng 15:585-593 (2002)). The enzyme fromPseudomonas aeruginosa, encoded by mdlC, has also been characterizedexperimentally (Barrowman et al., 34:57-60 (1986)). Additional genecandidates from Pseudomonas stutzeri, Pseudomonas fluorescens and otherorganisms can be inferred by sequence homology or identified using agrowth selection system developed in Pseudomonas putida (Henning et al.,Appl. Environ. Microbiol. 72:7510-7517 (2006)).

Protein GenBank ID GI Number Organism mdlC P20906.2 3915757 Pseudomonasputida mdlC Q9HUR2.1 81539678 Pseudomonas aeruginosa dpgB ABN80423.1126202187 Pseudomonas stutzeri ilvB-1 YP_260581.1 70730840 Pseudomonasfluorescens

A third enzyme capable of decarboxylating 2-oxoacids isalpha-ketoglutarate decarboxylase (KGD). The substrate range of thisclass of enzymes has not been studied to date. An exemplary KDC isencoded by kad in Mycobacterium tuberculosis (Tian et al., PNAS102:10670-10675 (2005)). KDC enzyme activity has also been detected inseveral species of rhizobia including Bradyrhizobium japonicum andMesorhizobium loti (Green et al., J Bacteriol 182:2838-2844 (2000)).Although the KDC-encoding gene(s) have not been isolated in theseorganisms, the genome sequences are available and several genes in eachgenome are annotated as putative KDCs. A KDC from Euglena gracilis hasalso been characterized but the gene associated with this activity hasnot been identified to date (Shigeoka et al., Arch. Biochem. Biophys.288:22-28 (1991)). The first twenty amino acids starting from theN-terminus were sequenced MTYKAPVKDVKFLLDKVFKV (SEQ ID NO.) (Shigeokaand Nakano, Arch. Biochem. Biophys. 288:22-28 (1991)). The gene could beidentified by testing candidate genes containing this N-terminalsequence for KDC activity.

Protein GenBank ID GI Number Organism kgd O50463.4 160395583Mycobacterium tuberculosis kgd NP_767092.1 27375563 Bradyrhizobiumjaponicum USDA110 kgd NP_105204.1 13473636 Mesorhizobium loti

A fourth candidate enzyme for catalyzing this reaction is branched chainalpha-ketoacid decarboxylase (BCKA). This class of enzyme has been shownto act on a variety of compounds varying in chain length from 3 to 6carbons (Oku et al., J Biol. Chem. 263:18386-18396 (1988); Smit et al.,Appl Environ Microbiol 71:303-311 (2005)). The enzyme in Lactococcuslactis has been characterized on a variety of branched and linearsubstrates including 2-oxobutanoate, 2-oxohexanoate, 2-oxopentanoate,3-methyl-2-oxobutanoate, 4-methyl-2-oxobutanoate and isocaproate (Smitet al., Appl Environ Microbiol 71:303-311 (2005)). The enzyme has beenstructurally characterized (Berg et al., Science. 318:1782-1786 (2007)).Sequence alignments between the Lactococcus lactis enzyme and thepyruvate decarboxylase of Zymomonas mobilus indicate that the catalyticand substrate recognition residues are nearly identical (Siegert et al.,Protein Eng Des Sel 18:345-357 (2005)), so this enzyme would be apromising candidate for directed engineering. Decarboxylation ofalpha-ketoglutarate by a BCKA was detected in Bacillus subtilis;however, this activity was low (5%) relative to activity on otherbranched-chain substrates (Oku and Kaneda, J Biol. Chem. 263:18386-18396(1988)) and the gene encoding this enzyme has not been identified todate. Additional BCKA gene candidates can be identified by homology tothe Lactococcus lactis protein sequence. Many of the high-scoring BLASTphits to this enzyme are annotated as indolepyruvate decarboxylases (EC4.1.1.74). Indolepyruvate decarboxylase (IPDA) is an enzyme thatcatalyzes the decarboxylation of indolepyruvate to indoleacetaldehyde inplants and plant bacteria. Recombinant branched chain alpha-keto aciddecarboxylase enzymes derived from the E1 subunits of the mitochondrialbranched-chain keto acid dehydrogenase complex from Homo sapiens and Bostaurus have been cloned and functionally expressed in E. coli (Davie etal., J. Biol. Chem. 267:16601-16606 (1992); Wynn et al., J. Biol. Chem.267:12400-12403 (1992); Wynn et al., J. Biol. Chem. 267:1881-1887(1992)). In these studies, the authors found that co-expression ofchaperonins GroEL and GroES enhanced the specific activity of thedecarboxylase by 500-fold (Wynn et al., J. Biol. Chem. 267:12400-12403(1992)). These enzymes are composed of two alpha and two beta subunits.

Protein GenBank ID GI Number Organism kdcA AAS49166.1 44921617Lactococcus lactis BCKDHB NP_898871.1 34101272 Homo sapiens BCKDHANP_000700.1 11386135 Homo sapiens BCKDHB P21839 115502434 Bos taurusBCKDHA P11178 129030 Bos taurus

Reduction of 3-buten-1-al to 3-buten-1-ol is catalyzed by an aldehydereductase or alcohol dehydrogenase. Genes encoding enzymes that catalyzethe reduction of an aldehyde to alcohol (i.e., alcohol dehydrogenase orequivalently aldehyde reductase) include alrA encoding a medium-chainalcohol dehydrogenase for C2-C14 (Tani et al., Appl. Environ. Microbiol.66:5231-5235 (2000)), yqhD and fucO from E. coli (Sulzenbacher et al.,342:489-502 (2004)), and bdh I and bdh II from C. acetobutylicum whichconverts butyraldehyde into butanol (Walter et al., 174:7149-7158(1992)). YqhD catalyzes the reduction of a wide range of aldehydes usingNADPH as the cofactor, with a preference for chain lengths longer thanC(3) (Sulzenbacher et al., 342:489-502 (2004); Perez et al., J. Biol.Chem. 283:7346-7353 (2008)). The adhA gene product from ZymomonasmobilisE has been demonstrated to have activity on a number of aldehydesincluding formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde,and acrolein (Kinoshita et al., Appl Microbiol Biotechnol 22:249-254(1985)). Additional aldehyde reductase candidates are encoded by bdh inC. saccharoperbutylacetonicum and Cbei_1722, Cbei_2181 and Cbei_2421 inC. Beijerinckii. Additional aldehyde reductase gene candidates inSaccharomyces cerevisiae include the aldehyde reductases GRE3, ALD2-6and HFD1, glyoxylate reductases GOR1 and YPL113C and glyceroldehydrogenase GCY1 (WO 2011/022651A1; Atsumi et al., Nature 451:86-89(2008)). The enzyme candidates described previously for catalyzing thereduction of methylglyoxal to acetol or lactaldehyde are also suitablelactaldehyde reductase enzyme candidates.

Protein GENBANK ID GI NUMBER ORGANISM alrA BAB12273.1 9967138Acinetobacter sp. strain M-1 ADH2 NP_014032.1 6323961 Saccharomycescerevisiae yqhD NP_417484.1 16130909 Escherichia coli fucO NP_417279.116130706 Escherichia coli bdh I NP_349892.1 15896543 Clostridiumacetobutylicum bdh II NP_349891.1 15896542 Clostridium acetobutylicumadhA YP_162971.1 56552132 Zymomonas mobilis bdh BAF45463.1 124221917Clostridium saccharoperbutyl- acetonicum Cbei_1722 YP_001308850150016596 Clostridium beijerinckii Cbei_2181 YP_001309304 150017050Clostridium beijerinckii Cbei_2421 YP_001309535 150017281 Clostridiumbeijerinckii GRE3 P38715.1 731691 Saccharomyces cerevisiae ALD2CAA89806.1 825575 Saccharomyces cerevisiae ALD3 NP_013892.1 6323821Saccharomyces cerevisiae ALD4 NP_015019.1 6324950 Saccharomycescerevisiae ALD5 NP_010996.2 330443526 Saccharomyces cerevisiae ALD6ABX39192.1 160415767 Saccharomyces cerevisiae HFD1 Q04458.1 2494079Saccharomyces cerevisiae GOR1 NP_014125.1 6324055 Saccharomycescerevisiae YPL113C AAB68248.1 1163100 Saccharomyces cerevisiae GCY1CAA99318.1 1420317 Saccharomyces cerevisiae

Enzymes exhibiting 4-hydroxybutyrate dehydrogenase activity (EC1.1.1.61) and glutarate semialdehyde reductase also fall into thiscategory. 4-Hydroxybutyrate dehydrogenase enzymes have beencharacterized in Ralstonia eutropha (Bravo et al., J Forens Sci,49:379-387 (2004)) and Clostridium kluyveri (Wolff et al., Protein Expr.Purif. 6:206-212 (1995)). Yet another gene is the alcohol dehydrogenaseadhI from Geobacillus thermoglucosidasius (Jeon et al., J Biotechnol135:127-133 (2008)). Glutarate semialdehyde reductase enzymes includethe ATEG_00539 gene product of Aspergillus terreus and 4-hydroxybutyratedehydrogenase of Arabidopsis thaliana, encoded by 4hbd (WO2010/068953A2). The A. thaliana enzyme was cloned and characterized inyeast (Breitkreuz et al., J. Biol. Chem. 278:41552-41556 (2003)).

PROTEIN GENBANK ID GI NUMBER ORGANISM 4hbd YP_726053.1 113867564Ralstonia eutropha H16 4hbd L21902.1 146348486 Clostridium kluyveri DSM555 adhI AAR91477.1 40795502 Geobacillus thermoglucosidasius ATEG_00539XP_001210625.1 115491995 Aspergillus terreus NIH2624 4hbd AAK94781.115375068 Arabidopsis thaliana

Another exemplary aldehyde reductase is methylmalonate semialdehydereductase, also known as 3-hydroxyisobutyrate dehydrogenase (EC1.1.1.31). This enzyme participates in valine, leucine and isoleucinedegradation and has been identified in bacteria, eukaryotes, andmammals. The enzyme encoded by P84067 from Thermus thermophilus HB8 hasbeen structurally characterized (Lokanath et al., J Mol Biol, 352:905-17(2005)). The reversibility of the human 3-hydroxyisobutyratedehydrogenase was demonstrated using isotopically-labeled substrate(Manning et al., Biochem J, 231:481-4 (1985)). Additional genes encodingthis enzyme include 3hidh in Homo sapiens (Hawes et al., MethodsEnzymol, 324:218-228 (2000)) and Oryctolagus cuniculus (Hawes et al.,supra; Chowdhury et al., Biosci. Biotechnol Biochem. 60:2043-2047(1996)), mmsB in Pseudomonas aeruginosa and Pseudomonas putida, and dhatin Pseudomonas putida (Aberhart et al., J. Chem. Soc. [Perkin 1]6:1404-1406 (1979); Chowdhury et al., Biosci. Biotechnol Biochem.60:2043-2047 (1996); Chowdhury et al., Biosci. Biotechnol Biochem.67:438-441 (2003)). Several 3-hydroxyisobutyrate dehydrogenase enzymeshave been characterized in the reductive direction, including mmsB fromPseudomonas aeruginosa (Gokarn et al., U.S. Pat. No. 739,676, (2008))and mmsB from Pseudomonas putida.

PROTEIN GENBANK ID GI NUMBER ORGANISM P84067 P84067 75345323 Thermusthermophilus 3hidh P31937.2 12643395 Homo sapiens 3hidh P32185.1 416872Oryctolagus cuniculus mmsB NP_746775.1 26991350 Pseudomonas putida mmsBP28811.1 127211 Pseudomonas aeruginosa dhat Q59477.1 2842618 Pseudomonasputida

EXAMPLE IV Preparation of a Butadiene Producing Microbial Organism witha but-3-En-1-Ol Pathway

This example describes the generation of a microbial organism capable ofproducing butadiene from pyruvate via a but-3-en-1-ol intermediate, inan organism engineered to have a butadiene pathway.

Escherichia coli is used as a target organism to engineer abutadiene-producing pathway. E. coli provides a good host for generatinga non-naturally occurring microorganism capable of producing butadiene.E. coli is amenable to genetic manipulation and is known to be capableof producing various products, including ethanol, acetic acid, formicacid, lactic acid, and succinic acid, effectively under anaerobic ormicroaerobic conditions.

To generate an E. coli strain engineered to produce the butadienepathway precursor, but-3-en-1-ol, a functional nucleic acids encodingthe enzymes utilized in the pathway described in Example III, areexpressed in E. coli using well known molecular biology techniques (see,for example, Sambrook, supra, 2001; Ausubel supra, 1999; Roberts et al.,supra, 1989).

In particular, an E. coli strain is engineered to produce but-3-en-1-olfrom pyruvate via the route described in Example 3. For the first stageof pathway construction, genes encoding enzymes to transform pyruvate tobut-3-en-1-ol are assembled onto a vector. The genes mhpE (AAC73455.1),mhpD (AAC73453.2), kdcA (AAS49166.1), adhA (YP_162971.1) encoding4-hydroxy-2-oxovalerate aldolase, 4-hydroxy-2-oxovalerate dehydratase,2-oxopentenoate decarboxylase and 3-buten-1-al reductase, respectively,are cloned into the pZE13 vector (Expressys, Ruelzheim, Germany), underthe control of the PA1/lacO promoter. The genes mvk (NP_357932.1), mvaK2(AAG02457.1) and, ispS (CAC35696.1) encoding alkyl phosphate kinase,alkyl diphosphate kinase and butadiene synthetase, respectively, arecloned into the pZA33 vector (Expressys, Ruelzheim, Germany) under thePA1/lacO promoter. The two plasmids are transformed into E. coli hoststrain containing lacI^(Q), which allows inducible expression byaddition of isopropyl-beta-D-1-thiogalactopyranoside (IPTG).

The resulting genetically engineered organism is cultured in glucosecontaining medium following procedures well known in the art (see, forexample, Sambrook et al., supra, 2001). The expression of butadienepathway genes is corroborated using methods well known in the art fordetermining polypeptide expression or enzymatic activity, including forexample, Northern blots, PCR amplification of mRNA and immunoblotting.Enzymatic activities of the expressed enzymes are confirmed using assaysspecific for the individually activities. The ability of the engineeredE. coli strain to produce butadiene is confirmed using HPLC, gaschromatography-mass spectrometry (GCMS) or liquid chromatography-massspectrometry (LCMS).

Microbial strains engineered to have a functional butadiene synthesispathway are further augmented by optimization for efficient utilizationof the pathway. Briefly, the engineered strain is assessed to determinewhether any of the exogenous genes are expressed at a rate limitinglevel. Expression is increased for any enzymes expressed at low levelsthat can limit the flux through the pathway by, for example,introduction of additional gene copy numbers. Strategies are alsoapplied to improve production of butadiene precursor but-3-en-1-ol, suchas mutagenesis, cloning and/or deletion of native genes involved inbyproduct formation.

To generate better butadiene producers, metabolic modeling is utilizedto optimize growth conditions. Modeling is also used to design geneknockouts that additionally optimize utilization of the pathway (see,for example, U.S. patent publications US 2002/0012939, US 2003/0224363,US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 andUS 2004/0009466, and in U.S. Pat. No. 7,127,379). Modeling analysisallows reliable predictions of the effects on cell growth of shiftingthe metabolism towards more efficient production of butadiene. Onemodeling method is the bilevel optimization approach, OptKnock (Burgardet al., Biotechnol. Bioengineer. 84:647-657 (2003)), which is applied toselect gene knockouts that collectively result in better production ofbutadiene. Adaptive evolution also can be used to generate betterproducers of, for example, the but-3-en-1-ol intermediate or thebutadiene product. Adaptive evolution is performed to improve bothgrowth and production characteristics (Fong and Palsson, Nat. Genet.36:1056-1058 (2004); Alper et al., Science 314:1565-1568 (2006)). Basedon the results, subsequent rounds of modeling, genetic engineering andadaptive evolution can be applied to the butadiene producer to furtherincrease production.

For large-scale production of butadiene, the above butadienepathway-containing organism is cultured in a fermenter using a mediumknown in the art to support growth of the organism under anaerobicconditions. Fermentations are performed in either a batch, fed-batch orcontinuous manner. Anaerobic conditions are maintained by first spargingthe medium with nitrogen and then sealing culture vessel (e.g., flaskscan be sealed with a septum and crimp-cap). Microaerobic conditions alsocan be utilized by providing a small hole for limited aeration. The pHof the medium is maintained at a pH of 7 by addition of an acid, such asH2SO4. The growth rate is determined by measuring optical density usinga spectrophotometer (600 nm), and the glucose uptake rate by monitoringcarbon source depletion over time. Byproducts such as undesirablealcohols, organic acids, and residual glucose can be quantified by HPLC(Shimadzu) with an HPX-087 column (BioRad), using a refractive indexdetector for glucose and alcohols, and a UV detector for organic acids,Lin et al., Biotechnol. Bioeng., 775-779 (2005).

EXAMPLE V Pathway for the Formation of Butadiene Precursor 3-Buten-2-Ol(but-2-En-1-Ol) from Acrylyl-CoA

This example describes pathways for converting acryl)-CoA to3-buten-2-ol, and further to butadiene. The conversion of acrylyl-CoA to3-buten-2-ol is accomplished in four enzymatic steps. Acrylyl-CoA andacetyl-CoA are first condensed to 3-oxopent-4-enoyl-CoA by abeta-ketothiolase. The 3-oxopent-4-enoyl-CoA product is subsequentlyhydrolyzed to 3-oxopent-4-enoate by a CoA hydrolase, transferase orsynthetase. Decarboxylation of the 3-ketoacid intermediate yields3-buten-2-al, which is further reduced to 3-buten-2-ol by an alcoholdehydrogenase or ketone reductase.

Enzymes and gene candidates for catalyzing but-3-en-2-ol pathwayreactions are described in further detail below.

Acrylyl-CoA and acetyl-CoA are condensed to form 3-oxopent-4-enoyl-CoAby a beta-ketothiolase (EC 2.3.1.16). Beta-ketothiolase enzymescatalyzing the formation of beta-ketovalerate from acetyl-CoA andpropionyl-CoA are good candidates for catalyzing the formation of3-oxopen-4-enoyl-CoA. Zoogloea ramigera possesses two ketothiolases thatcan form beta-ketovaleryl-CoA from propionyl-CoA and acetyl-CoA and R.eutropha has a beta-oxidation ketothiolase that is also capable ofcatalyzing this transformation (Gruys et al., U.S. Pat. No. 5,958,745).The sequences of these genes or their translated proteins have not beenreported, but several genes in R. eutropha, Z. ramigera, or otherorganisms can be identified based on sequence homology to bktB from R.eutropha.

Protein GenBank ID GI Number Organism phaA YP_725941.1 113867452Ralstonia eutropha h16_A1713 YP_726205.1 113867716 Ralstonia eutrophapcaF YP_728366.1 116694155 Ralstonia eutropha h16_B1369 YP_840888.1116695312 Ralstonia eutropha h16_A0170 YP_724690.1 113866201 Ralstoniaeutropha h16_A0462 YP_724980.1 113866491 Ralstonia eutropha h16_A1528YP_726028.1 113867539 Ralstonia eutropha h16_B0381 YP_728545.1 116694334Ralstonia eutropha h16_B0662 YP_728824.1 116694613 Ralstonia eutrophah16_B0759 YP_728921.1 116694710 Ralstonia eutropha h16_B0668 YP_728830.1116694619 Ralstonia eutropha h16_A1720 YP_726212.1 113867723 Ralstoniaeutropha h16_A1887 YP_726356.1 113867867 Ralstonia eutropha phbAP07097.4 135759 Zoogloea ramigera bktB YP_002005382.1 194289475Cupriavidus taiwanensis Rmet_1362 YP_583514.1 94310304 Ralstoniametallidurans Bphy_0975 YP_001857210.1 186475740 Burkholderia phymatum

Additional enzymes include beta-ketothiolases that are known to converttwo molecules of acetyl-CoA into acetoacetyl-CoA (EC 2.1.3.9). Exemplaryacetoacetyl-CoA thiolase enzymes include the gene products of atoB fromE. coli (Martin et al., Nat. Biotechnol. 21:796-802 (2003)), thlA andthlB from C. acetobutylicum (Hanai et al., Appl. Environ. Microbiol.73:7814-7818 (2007); Winzer et al., J. Mol. Microbiol. Biotechnol.2:531-541 (2000)), and ERG10 from S. cerevisiae (Hiser et al., J. Biol.Chem. 269:31383-31389 (1994)).

Protein GenBank ID GI Number Organism atoB NP_416728 16130161Escherichia coli thlA NP_349476.1 15896127 Clostridium acetobutylicumthlB NP_149242.1 15004782 Clostridium acetobutylicum ERG10 NP_0152976325229 Saccharomyces cerevisiae

Beta-ketoadipyl-CoA thiolase (EC 2.3.1.174), also called 3-oxoadipyl-CoAthiolase, converts beta-ketoadipyl-CoA to succinyl-CoA and acetyl-CoA,and is a key enzyme of the beta-ketoadipate pathway for aromaticcompound degradation. The enzyme is widespread in soil bacteria andfungi including Pseudomonas putida (Harwood et al., J. Bacteriol.176-6479-6488 (1994)) and Acinetobacter calcoaceticus (Doten et al., J.Bacteriol. 169:3168-3174 (1987)). The P. putida enzyme is a homotetramerbearing 45% sequence homology to beta-ketothiolases involved in PHBsynthesis in Ralstonia eutropha, fatty acid degradation by humanmitochondria and butyrate production by Clostridium acetobutylicum(Harwood et al., supra). A beta-ketoadipyl-CoA thiolase in Pseudomonasknackmussii (formerly sp. B13) has also been characterized (Gobel etal., J. Bacteriol. 184:216-223 (2002); Kaschabek et al., supra).

Protein GenBank ID GI Number Organism pcaF NP_743536.1 506695Pseudomonas putida pcaF AAC37148.1 141777 Acinetobacter calcoaceticuscatF Q8VPF1.1 75404581 Pseudomonas knackmussii

Removal of the CoA moiety of 3-oxopent-4-enoyl-CoA product is catalyzed,for example, by 3-oxopent-4-enoyl-CoA hydrolase. The CoA hydrolaseencoded by acot12 from Rattus norvegicus brain (Robinson et al.,Biochem. Biophys. Res. Commun. 71:959-965 (1976)) can react with severalalternate substrates including butyryl-CoA, hexanoyl-CoA andmalonyl-CoA. The human dicarboxylic acid thioesterase, encoded by acot8,exhibits activity on glutaryl-CoA, adipyl-CoA, suberyl-CoA, sebacyl-CoA,and dodecanedioyl-CoA (Westin et al., J. Biol. Chem. 280:38125-38132(2005)). The closest E. coli homolog to this enzyme, tesB, can alsohydrolyze a range of CoA thiolesters (Naggert et al., J Biol Chem266:11044-11050 (1991)). A similar enzyme has also been characterized inthe rat liver (Deana R., Biochem Int 26:767-773 (1992)). Additionalenzymes with hydrolase activity in E. coli include ybgC, paaI, and ybdB(Kuznetsova, et al., FEMS Microbiol Rev, 2005, 29(2):263-279; Song etal., J Biol Chem, 2006, 281(16):11028-38). Though its sequence has notbeen reported, the enzyme from the mitochondrion of the pea leaf has abroad substrate specificity, with demonstrated activity on acetyl-CoA,propionyl-CoA, butyryl-CoA, palmitoyl-CoA, oleoyl-CoA, succinyl-CoA, andcrotonyl-CoA (Zeiher et al., Plant. Physiol. 94:20-27 (1990)) Theacetyl-CoA hydrolase, ACH1, from S. cerevisiae represents anothercandidate hydrolase (Buu et al., J. Biol. Chem. 278:17203-17209 (2003)).

Protein GenBank Accession # GI# Organism acot12 NP_570103.1 18543355Rattus norvegicus tesB NP_414986 16128437 Escherichia coli acot8CAA15502 3191970 Homo sapiens acot8 NP_570112 51036669 Rattus norvegicustesA NP_415027 16128478 Escherichia coli ybgC NP_415264 16128711Escherichia coli paaI NP_415914 16129357 Escherichia coli ybdB NP_41512916128580 Escherichia coli ACH1 NP_009538 6319456 Saccharomycescerevisiae

Additional hydrolase enzymes include 3-hydroxyisobutyryl-CoA hydrolasewhich has been described to efficiently catalyze the conversion of3-hydroxyisobutyryl-CoA to 3-hydroxyisobutyrate during valinedegradation (Shimomura et al., J Biol. Chem. 269:14248-14253 (1994)).Genes encoding this enzyme include hibch of Rattus norvegicus (Shimomuraet al., Methods Enzymol. 324:229-240 (2000)) and Homo sapiens (Shimomuraet al., supra). Similar gene candidates can also be identified bysequence homology, including hibch of Saccharomyces cerevisiae andBC_2292 of Bacillus cereus.

GenBank Protein Accession # GI# Organism hibch Q5XIE6.2 146324906 Rattusnorvegicus hibch Q6NVY1.2 146324905 Homo sapiens hibch P28817.2 2506374Saccharomyces cerevisiae BC_2292 AP09256 29895975 Bacillus cereus

Decarboxylation of 3-oxopent-4-enoate is catalyzed by a 3-ketoaciddecarboxylase. The acetoacetate decarboxylase (EC 4.1.1.4) fromClostridium acetobutylicum, encoded by adc, has a broad substratespecificity and has been shown to decarboxylate numerous alternatesubstrates including 2-ketocyclohexane carboxylate, 3-oxopentanoate,2-oxo-3-phenylpropionic acid, 2-methyl-3-oxobutyrate and benzoyl-acetate(Rozzel et al., J. Am. Chem. Soc. 106:4937-4941 (1984); Benner andRozzell, J. Am. Chem. Soc. 103:993-994 (1981); Autor et al., J. Biol.Chem. 245:5214-5222 (1970)). An acetoacetate decarboxylase has also beencharacterized in Clostridium beijerinckii (Ravagnani et al., Mol.Microbiol 37:1172-1185 (2000)). The acetoacetate decarboxylase fromBacillus polymyxa, characterized in cell-free extracts, also has a broadsubstrate specificity for 3-keto acids and can decarboxylate3-oxopentanoate (Matiasek et al., Curr. Microbiol 42:276-281 (2001)).The gene encoding this enzyme has not been identified to date and thegenome sequence of B. polymyxa is not yet available. Another adc isfound in Clostridium saccharoperbutylacetonicum (Kosaka, et al., Biosci.Biotechnol Biochem. 71:58-68 (2007)). Additional gene candidates inother organisms, including Clostridium botulinum and Bacillusamyloliquefaciens FZB42, can be identified by sequence homology.

Protein GenBank ID GI No. Organism adc NP_149328.1 15004868 Clostridiumacetobutylicum adc AAP42566.1 31075386 Clostridium saccharoperbutyl-acetonicum adc YP_001310906.1 150018652 Clostridium beijerinckiiCLL_A2135 YP_001886324.1 187933144 Clostridium botulinum RBAM_030030YP_001422565.1 154687404 Bacillus amyloliquefaciens

Reduction of 3-buten-2-al to 3-buten-2-ol is catalyzed by an alcoholdehydrogenase or ketone reductase. Alcohol dehydrogenases describedabove in Example III are also suitable candidates for thistransformation. There exist several exemplary alcohol dehydrogenasesthat convert a ketone to a hydroxyl functional group. Two such enzymesfrom E. coli are encoded by malate dehydrogenase (mdh) and lactatedehydrogenase (ldhA). In addition, lactate dehydrogenase from Ralstoniaeutropha has been shown to demonstrate high activities on 2-ketoacids ofvarious chain lengths includings lactate, 2-oxobutyrate, 2-oxopentanoateand 2-oxoglutarate (Steinbuchel et al., Eur. J. Biochem. 130:329-334(1983)). Conversion of alpha-ketoadipate into alpha-hydroxyadipate canbe catalyzed by 2-ketoadipate reductase, an enzyme reported to be foundin rat and in human placenta (Suda et al., Arch. Biochem. Biophys.176:610-620 (1976); Suda et al., Biochem. Biophys. Res. Commun.77:586-591 (1977)). An additional oxidoreductase is the mitochondrial3-hydroxybutyrate dehydrogenase (bdh) from the human heart which hasbeen cloned and characterized (Marks et al., J. Biol. Chem.267:15459-15463 (1992)). Alcohol dehydrogenase enzymes of C.beijerinckii (Ismaiel et al., J. Bacteriol. 175:5097-5105 (1993)) and T.brockii (Lamed et al., Biochem. J. 195:183-190 (1981); Peretz et al.,Biochemistry. 28:6549-6555 (1989)) convert acetone to isopropanol.Methyl ethyl ketone reductase catalyzes the reduction of MEK to2-butanol. Exemplary MEK reductase enzymes can be found in Rhodococcusruber (Kosjek et al., Biotechnol Bioeng. 86:55-62 (2004)) and Pyrococcusfuriosus (van der Oost et al., Eur. J. Biochem. 268:3062-3068 (2001)).

GenBank Gene Accession No. GI No. Organism mdh AAC76268.1 1789632Escherichia coli ldhA NP_415898.1 16129341 Escherichia coli ldhYP_725182.1 113866693 Ralstonia eutropha bdh AAA58352.1 177198 Homosapiens adh AAA23199.2 60592974 Clostridium beijerinckii NRRL B593 adhP14941.1 113443 Thermoanaerobacter brockii HTD4 sadh CAD36475 21615553Rhodococcus ruber adhA AAC25556 3288810 Pyrococcus furiosus

Enzymes that catalyze the reduction of 3-oxobutanol to 1,3-butanediolare also applicable here. Such enzymes are found in organisms of thegenus Bacillus, Brevibacterium, Candida, and Klebsiella among others, asdescribed by Matsuyama et al. J Mol Cat B Enz, 11:513-521 (2001). One ofthese enzymes, SADH from Candida parapsilosis, was cloned andcharacterized in E. coli. A mutated Rhodococcus phenylacetaldehydereductase (Sar268) and a Leifonia alcohol dehydrogenase have also beenshown to catalyze this transformation at high yields (Itoh et al., Appl.Microbiol Biotechnol. 75:1249-1256 (2007)).

Gene GenBank Accession No. GI No. Organism sadh BAA24528.1 2815409Candida parapsilosis

EXAMPLE VI Preparation of a Butadiene Producing Microbial Organism witha but-3-En-2-Ol Pathway

This example describes the generation of a microbial organism capable ofproducing butadiene from pyruvate via a but-3-en-2-ol intermediate, inan organism engineered to have a butadiene pathway.

Escherichia coli is used as a target organism to engineer abutadiene-producing pathway. E. coli provides a good host for generatinga non-naturally occurring microorganism capable of producing butadiene.E. coli is amenable to genetic manipulation and is known to be capableof producing various products, including ethanol, acetic acid, formicacid, lactic acid, and succinic acid, effectively under anaerobic ormicroaerobic conditions.

To generate an E. coli strain engineered to produce the butadienepathway precursor, but-3-en-2-ol, a functional nucleic acids encodingthe enzymes utilized in the pathway described in Example III, areexpressed in E. coli using well known molecular biology techniques (see,for example, Sambrook, supra, 2001; Ausubel supra, 1999; Roberts et al.,supra, 1989).

In particular, an E. coli strain is engineered to produce but-3-en-2-olfrom acrylyl-CoA via the route described in Example III. For the firststage of pathway construction, genes encoding enzymes to transformacrylyl-CoA to but-3-en-2-ol are assembled onto a vector. The genes phaA(YP_725941.1), tesB (NP_414986), adc (NP_149328.1) and sadh (BAA24528.1)encoding beta-ketothiolase, 3-oxopent-4-enoyl-CoA hydrolase,3-oxopent-4-enoate decarboxylase and 3-buten-2-one reductase,respectively, are cloned into the pZE13 vector (Expressys, Ruelzheim,Germany), under the control of the PA1/lacO promoter. The genes mvk(NP_357932.1), mvaK2 (AAG02457.1) and, ispS (CAC35696.1) encoding alkylphosphate kinase, alkyl diphosphate kinase and butadiene synthetase,respectively, are cloned into the pZA33 vector (Expressys, Ruelzheim,Germany) under the PA1/lacO promoter. The two plasmids are transformedinto E. coli host strain containing lacI^(Q), which allows inducibleexpression by addition of isopropyl-beta-D-1-thiogalactopyranoside(IPTG).

The resulting genetically engineered organism is cultured in glucosecontaining medium following procedures well known in the art (see, forexample, Sambrook et al., supra, 2001). The expression of butadienepathway genes is corroborated using methods well known in the art fordetermining polypeptide expression or enzymatic activity, including forexample, Northern blots, PCR amplification of mRNA and immunoblotting.Enzymatic activities of the expressed enzymes are confirmed using assaysspecific for the individually activities. The ability of the engineeredE. coli strain to produce butadiene is confirmed using HPLC, gaschromatography-mass spectrometry (GCMS) or liquid chromatography-massspectrometry (LCMS).

Microbial strains engineered to have a functional butadiene synthesispathway are further augmented by optimization for efficient utilizationof the pathway. Briefly, the engineered strain is assessed to determinewhether any of the exogenous genes are expressed at a rate limitinglevel. Expression is increased for any enzymes expressed at low levelsthat can limit the flux through the pathway by, for example,introduction of additional gene copy numbers. Strategies are alsoapplied to improve production of butadiene precursor but-3-en-2-ol, suchas mutagenesis, cloning and/or deletion of native genes involved inbyproduct formation.

To generate better butadiene producers, metabolic modeling is utilizedto optimize growth conditions. Modeling is also used to design geneknockouts that additionally optimize utilization of the pathway (see,for example, U.S. patent publications US 2002/0012939, US 2003/0224363,US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 andUS 2004/0009466, and in U.S. Pat. No. 7,127,379). Modeling analysisallows reliable predictions of the effects on cell growth of shiftingthe metabolism towards more efficient production of butadiene. Onemodeling method is the bilevel optimization approach, OptKnock (Burgardet al., Biotechnol. Bioengineer. 84:647-657 (2003)), which is applied toselect gene knockouts that collectively result in better production ofbutadiene. Adaptive evolution also can be used to generate betterproducers of, for example, the but-3-en-2-ol intermediate or thebutadiene product. Adaptive evolution is performed to improve bothgrowth and production characteristics (Fong and Palsson, Nat. Genet.36:1056-1058 (2004); Alper et al., Science 314:1565-1568 (2006)). Basedon the results, subsequent rounds of modeling, genetic engineering andadaptive evolution can be applied to the butadiene producer to furtherincrease production.

For large-scale production of butadiene, the above butadienepathway-containing organism is cultured in a fermenter using a mediumknown in the art to support growth of the organism under anaerobicconditions. Fermentations are performed in either a batch, fed-batch orcontinuous manner. Anaerobic conditions are maintained by first spargingthe medium with nitrogen and then sealing culture vessel (e.g., flaskscan be sealed with a septum and crimp-cap). Microaerobic conditions alsocan be utilized by providing a small hole for limited aeration. The pHof the medium is maintained at a pH of 7 by addition of an acid, such asH2SO4. The growth rate is determined by measuring optical density usinga spectrophotometer (600 nm), and the glucose uptake rate by monitoringcarbon source depletion over time. Byproducts such as undesirablealcohols, organic acids, and residual glucose can be quantified by HPLC(Shimadzu) with an HPX-087 column (BioRad), using a refractive indexdetector for glucose and alcohols, and a UV detector for organic acids,Lin et al., Biotechnol. Bioeng., 775-779 (2005).

Throughout this application various publications have been referenced.The disclosures of these publications in their entireties, includingGenBank and GI number publications, are hereby incorporated by referencein this application in order to more fully describe the state of the artto which this invention pertains. Although the invention has beendescribed with reference to the examples provided above, it should beunderstood that various modifications can be made without departing fromthe spirit of the invention.

What is claimed is:
 1. A non-naturally occurring microbial organism,said microbial organism having an alkene pathway and comprising at leastone exogenous nucleic acid encoding an alkene pathway enzyme expressedin a sufficient amount to convert an alcohol to an alkene, wherein saidalkene pathway comprises alkene pathway enzymes selected from: (1) analcohol kinase that transfers a phosphate group to a hydroxyl group, anda phosphate lyase that converts an alkyl-phosphate to an alkene, whereinthe alcohol kinase is selected from enzymes having an E.C. numberselected from the group consisting of 2.7.1.30 (glycerol kinase),2.7.1.36 (mevalonate kinase), or 2.7.1.39 (homoserine kinase); (2) adiphosphokinase that transfers a di-phosphate group to a hydroxyl groupand a diphosphate lyase that converts an alkyl di-phosphate to analkene, wherein the diphosphokinase is selected from enzymes having anE.C. number selected from the group consisting of, 2.7.6.1(ribose-phosphate diphosphokinase) or 2.7.6.2 (thiaminediphosphokinase); or (3) an alcohol kinase that transfers a phosphategroup to a hydroxyl group, an alkyl phosphate kinase that transfers aphosphate group to a phosphate group of an alkyl-phosphate, and adiphosphate lyase that converts an alkyl di-phosphate to an alkene,wherein: (i) the alcohol kinase is selected from enzymes having an E.C.number selected from the group consisting of 2.7.1.30 (glycerol kinase),2.7.1.36 (mevalonate kinase), or 2.7.1.39 (homoserine kinase); (ii) thealkyl phosphate kinase is selected from enzymes having an E.C. numberselected from the group consisting of 2.7.4.2 (phosphomevalonatekinase), 2.7.4.18 (farnesyl-diphosphate kinase); and (iii) thediphosphate lyase is selected from enzymes having an E.C. numberselected from the group consisting of 4.2.3.5 (Chorismate synthase),4.2.3.15 (Myrcene synthase), 4.2.3.36 (Terpentriene synthase), 4.2.3.46((E, E)-alpha-Farnesene synthase), or 4.2.3.47 (Beta-Farnesenesynthase); wherein said alcohol is a compound of Formula (I)

and wherein said alkene is a compound of Formula (II)

wherein, (a) R¹, R², R³, and R⁴ of Formula I and R¹, R², R³, and R⁴ ofFormula II are the same and are independently hydrogen or linearsaturated C₁₋₆ alkyl, and (b) wherein R¹, R², R³, and R⁴ are selectedsuch that the compound of Formula (II) is a linear saturated C₈ alkene.2. The non-naturally occurring microbial organism of claim 1, whereinsaid microbial organism comprises two exogenous nucleic acids eachencoding an alkene pathway enzyme when the microbial organism comprisesan alkene pathway selected from (1) or (2) and the microbial organismcomprises two or three exogenous nucleic acids each encoding an alkenepathway enzyme when the microbial organism comprises an alkene pathwayselected from (3).
 3. The non-naturally occurring microbial organism ofclaim 2, wherein said two exogenous nucleic acids encode an alcoholkinase and a phosphate lyase.
 4. The non-naturally occurring microbialorganism of claim 2, wherein said two exogenous nucleic acids encode adiphosphokinase and a diphosphate lyase.
 5. The non-naturally occurringmicrobial organism of claim 2, wherein said three exogenous nucleicacids encode an alcohol kinase, an alkyl phosphate kinase and adiphosphate lyase.
 6. The non-naturally occurring microbial organism ofclaim 1, wherein said at least one exogenous nucleic acid is aheterologous nucleic acid.
 7. The non-naturally occurring microbialorganism of claim 1, wherein said non-naturally occurring microbialorganism is in a substantially anaerobic culture medium.
 8. A method forproducing an alkene comprising culturing the non-naturally occurringmicrobial organism of claim 1 comprising said alkene pathway underconditions and for a sufficient period of time to produce a linearsaturated C₈ alkene of Formula (II) of claim
 1. 9. The non-naturallyoccurring microbial organism of claim 3, wherein the alcohol kinase is:(1) a mevalonate kinase from Saccharomyces cerevisiae,Methanocaldococcus jannaschi, Homo sapiens, Arabidopsis thaliana col.,Methanosarcina mazei or Streptococcus pneumonia; (2) a glycerol kinasefrom Escherichia coli, Saccharomyces cerevisiae, or Thermotoga maritime;or (3) a homoserine kinase from Escherichia coli, Saccharomycescerevisiae or Streptomyces sp. ACT-1.
 10. The non-naturally occurringmicrobial organism of claim 3, wherein the alcohol kinase is: (1) amevalonate kinase corresponding to GenBank ID: CAA39359.1, CAA39359.1(GI number: 3684), AAH16140.1 (GI number 16359371), NP_851084.1 (GInumber 30690651), NP_633786.1 (GI number 21227864), or NP_357932.1 (GInumber 15902382); (2) a glycerol kinase corresponding to GenBank ID:AP_003883.1 (GI number 89110103), NP_228760.1 (GI number 15642775),NP_229230.1 (GI number 15642775), or NP_011831.1 (GI number 82795252);or (3) a homoserine kinase corresponding to GenBank ID: BAB96580.2 (GInumber 85674277), ZP_06280784.1 (GI number 282871792), or AAA35154.1 (GInumber 172978).
 11. The non-naturally occurring microbial organism ofclaim 3, wherein the phosphate lyase is: (1) a chorismate synthase fromEscherichia coli, Streptococcus pneumoniae, Neurospora crassa, orSaccharomyces cerevisiae; (2) a myrcene synthase from Solanumlycopersicum, Picea abies, Abies grandis, or Arabidopsis thaliana; or(3) a farnesyl diphosphate from Arabidopsis thaliana, Picea abies,Cucumis sativus, Matus×domestica, or Zea mays.
 12. The non-naturallyoccurring microbial organism of claim 3, wherein the phosphate lyase is:(1) a chorismate synthase corresponding to GenBank ID: NP_416832.1 (GInumber 16130264), ACH47980.1 (GI number 197205483), AAC49056.1 (GInumber 976375), or CAA42745.1 (GI number 3387); (2) a myrcene synthasecorresponding to GenBank ID: ACN58229.1 (GI number 224579303),AAS47690.2 (GI number 77546864), 024474.1 (GI number 17367921), orEC07543.1 (GI number 330252449); or (3) a farnesyl diphosphatecorresponding to GenBank ID: A4FVP2.1 (GI number 205829248), POCJ43.1(GI number 317411866), AAS47697.1 (GI number 44804601), AAU05951.1 (GInumber 51537953), Q84LB2.2 (GI number 75241161), or Q84ZW8.1 (GI number75149279).
 13. The non-naturally occurring microbial organism of claim5, wherein the alcohol kinase is: (1) a mevalonate kinase fromSaccharomyces cerevisiae, Methanocaldococcus jannaschi, Homo sapiens,Arabidopsis thaliana col., Methanosarcina mazei or Streptococcuspneumonia; (2) a glycerol kinase from Escherichia coli, Saccharomycescerevisiae, or Thermotoga maritime; or (3) a homoserine kinase fromEscherichia coli, Saccharomyces cerevisiae or Streptomyces sp. ACT-1.14. The non-naturally occurring microbial organism of claim 5, whereinthe alcohol kinase is: (1) a mevalonate kinase corresponding to GenBankID: CAA39359.1 (GI number 3684), Q58487.1 (2497517), AAH16140.1 (GInumber 16359371), NP_851084.1 (GI number 30690651), NP_633786.1 (GInumber 21227864), or NP_357932.1 (GI number 15902382); (2) a glycerolkinase corresponding to GenBank ID: AP_003883.1 (GI number 89110103),NP_228760.1 (GI number 15642775), NP_229230.1 (GI number 15642775), orNP_011831.1 (GI number 82795252); or (3) a homoserine kinasecorresponding to GenBank ID: BAB96580.2 (GI number 85674277),ZP_06280784.1 (GI number 282871792), or AAA35154.1 (GI number 172978).15. The non-naturally occurring microbial organism of claim 5, whereinthe diphosphate lyase is: (1) a chorismate synthase from Escherichiacoli, Streptococcus pneumoniae, Neurospora crassa, or Saccharomycescerevisiae; (2) a myrcene synthase from Solanum lycopersicum, Piceaabies, Abies Grandis, or Arabidopsis thaliana; or (3) a farnesyldiphosphate from Arabidopsis thaliana, Picea abies, Cucumis sativus,Matus×domestica, or Zea mays.
 16. The non-naturally occurring microbialorganism of claim 5, wherein the diphosphate lyase is: (1) a chorismatesynthase corresponding to GenBank ID: NP_416832.1 (GI number 16130264),ACH47980.1 (GI number 197205483), AAC49056.1 (GI number 976375), orCAA42745.1 (GI number 3387); (2) a myrcene synthase corresponding toGenBank ID: ACN58229.1 (GI number 224579303), AAS47690.2 (GI number77546864), 024474.1 (GI number 17367921), or EC07543.1 (GI number330252449); or (3) a farnesyl diphosphate corresponding to GenBank ID:A4FVP2.1 (GI number 205829248), POCJ43.1 (GI number 317411866),AAS47697.1 (GI number 44804601), AAU05951.1 (GI number 51537953),Q84LB2.2 (GI number 75241161), or Q84ZW8.1 (GI number 75149279).
 17. Thenon-naturally occurring microbial organism of claim 5, wherein the alkylphosphate kinase is: (1) a phosphomevalonate kinase from Saccharomycescerevisiae, Staphylococcus aureus, Streptococcus pneumoniae, orEnterococcus faecalis, or (2) a farnesyl monophosphate kinase fromNicotiana tabacum.
 18. The non-naturally occurring microbial organism ofclaim 5, wherein the alkyl phosphate kinase is a phosphomevalonatekinase corresponding to GenBank ID: AAA34596.1 (GI number 171479),AAG02426.1 (GI number 9937366), AAG02457.1 (GI number 9937409), orAAG02442.1 (GI number 9937388).